Firearms History, Technology & Development

Rifle Shooting Positions: The Offhand Stance

2011-11-06T22:09:00.000-08:00

Well, it has been a while since the last post on this blog, so let's continue where we left off: shooting positions. In this post, we will look into various rifle shooting positions.

The most common shooting positions used in rifles are: off-hand, kneeling and prone position. The sitting position is used to a lesser degree and the back position is not used as much these days. We will discuss all of them in this and subsequent posts.

It must be noted in our discussions, that we take the perspective of a right-handed shooter. For left handers, one may substitute "left" for "right" and vice-versa.

The first position we will study is the off-hand position, otherwise known as the standing position:

Image taken from W.W. Greener's The Gun and its Development, 1910. Image is now in public domain.

Click on image to enlarge

This is a commonly used position, often used for shorter ranges and in the field. It is also taught by the US military. Notice that the feet are positioned about a shoulder width apart. The left foot is forward and pointing roughly in the direction of the target and the right foot is placed back and is almost at a right angle to the target. The legs are positioned to give the shooter a firm stance. The rifle is positioned across the chest of the shooter and the left hand is located comfortably gripping the fore-grip. Notice that the left elbow is right below the rifle, not angled to one side.

It might be worthwhile to note that in the above image, we notice that the left arm is somewhat extended out. This is called the "arm-out" off-hand position and is more suitable for shooting at moving targets, because it allows the user to rotate the upper body easier to track a target.

For a more static target, some users prefer to position the left arm much closer to the body (i.e. the arm-back offhand stance)

Notice that in the above image, the left hand is positioned close to the rifle action and the left elbow is very close to the body. While the arm-back position allows for more steadiness, it doesn't allow the user to readjust as easily as the arm-out position, if the target moves. Hence, this stance is more commonly used against static targets.

In the next post, we will look at the kneeling position.

September 11th 2011 - Never Forget!

2011-09-11T20:20:00.001-07:00

September 11th - Never Forget.

Shooting Positions

2011-08-14T14:46:00.000-07:00

In the next series of posts, we will look into the subject of shooting positions. There are many positions that one may shoot a firearm from: standing upright, kneeling, lying down, holding the firearm with only one hand, holding it with both hands, standing sideways and (if John Woo movies are any authority on shooting) jumping out of a door with a Beretta 92F pistol in each hand and firing alternately while in the air in slow motion, while a flock of white doves fly out :).

Back in the days when muzzle loaders were popular and rifling was non-existent, soldiers generally stood upright in lines of three and shot at each other. There were good reasons to do this:

Without rifling, firearm accuracy wasn't very good. But if you lined up a group of men and asked them to shoot a target, chances were good at least one of them would hit something, even if it wasn't the target he was aiming for.
With a muzzle loader, the user stands it upright with the butt on the ground, pours some gunpowder into the barrel via the muzzle, then inserts a ball and wadding into the muzzle and then rams them down the barrel with a ramrod. These operations are not possible to do sitting down, especially when the muzzle-loader is some 4-5 feet long.
It was considered more macho and gentlemanly by Europeans, to shoot from a position where the enemy can see you, rather than shooting the enemy from behind cover.

In the early 1800s to about the 1840s, the British rifleman had a rifle with a handle extending down from the trigger guard. When this was grabbed with the left hand, it put the left arm at an angle that steadied it against the body.

A British Rifleman from the 1800s. Image taken from W.W. Greener's The Gun and its Development, now in public domain. Click on the image to enlarge.

As you can see, this position is nothing like modern shooting positions. However, this was a common position used by many European armies and shooting enthusiasts in the early 1800s.

We also have this account by a Dr. Scoffern, that describes the technique of shooting used by Swiss shooters:
"As regards the Swiss system of loading and firing, both are peculiar. The Switzer unslings a powder-flask of large dimension and turns in a charge of about 2.5 drams of powder. From a side pocket, he next extracts a linen patch, and, putting it into his mouth, turns it round and round, very much as Jack turns his quid. The Switzer's object is to saturate his patch with saliva. This is his way of solving the lubrication difficulty, and, mind me, it is not a bad one. His next move is to lay the patch upon the bore and the picket upon that: which being done, he takes the ramrod in both hands and drives the picket home with one thrust. To be assured that it is home, the Switzer jerks the ramrod down upon it with a ringing thwack. 'Bad practice,' you say: 'he meals the powder'. Not a bit of it! At the end of the ramrod there is a flat iron boss, which only permits it to fall down to a fixed and unvarying extent. Well, the anxious moments of firing are now come round. See how the Switzer employs them. He begins by planting his legs wide apart, left leg foremost. He tries the ground under him for a moment or so, to find whether it be soft, and if he can wriggle out two little graves, one for each foot, the better. Should you have turned away your eye for a moment, and then direct your glance at the Switzer again, you would have found him half as big again as you last saw him. He has puffed himself out with a deep breathing, like the frog who aspired to become a bull. By this deep inspiration, the Switzer has stiffened himself, just after the way one takes the limpness out of a macintosh cushion -- by filling it full of wind. The Switzer is firm planted and rigid now -- he could no more bend from side to side than can a hard rammed sausage. If he were obliged to hold his wind as long as we take to tell our tale, it would be bad for him -- he would burst outright, like an overcharged rifle. Well, with legs apart (like a little Rhodian Colossus) and bated breath, the Switzer shoulders his piece. At the end of the stock is a boss, which he tucks between his right arm and right ribs. Gathering his two hands close together, he rests his rifle on his left hand, placed close in front of the trigger guard; pressing his left elbow, not on the left knee, indeed, but upon the left hip. Lot's wife could hardly be more rigid. Limited power of motion, nevertheless, the Switzer has. Heavenward you see his rifle pointing, and if you observe the Switzer's nose (that organ given only for ornament, as some affirm), it has turned to a purpose of utility. The Switzer is steadying the butt-end of his rifle against it; his nose is a lateral rest. By this time that nose is red on the tip, the face turgid, the eyes projecting. The Switzer's whole position is decidedly not graceful -- one very suggestive of extrusion. Heavenward you see it pointing. Gradually down and down it drops. The blank is seen, the trigger pressed. Rifle crack and Switzer's grunt follow on the heels of each other. He could not hold his breath for ever. Picket and unpreserved breath fly together. Behold him now, panting and puffing like a Cingalese pearl-diver fresh from the worrying of a ground shark. Decidedly, our style of rifle-firing is more graceful and quick."

Method of holding Rifle and Position of Swiss Rifle Shot. Click on image to enlarge. Public domain image.

While Dr. Scoffern might not have thought the Swiss style as "graceful", it was a very effective style, as the Swiss won the majority of prizes as the first British National Rifle Association competition held at Wimbledon in 1860. It must be noted that the Swiss shooters made sure that they had a stable shooting position before pulling the trigger, something that is still emphasized in training today.

In the next few posts, we will look into more shooting positions, both historical and modern.

Cleaning Firearms: Modern Methods

2011-08-08T23:53:00.000-07:00

In the last post, we studied some historic instructions on cleaning firearms. Actually, most of what was stated in that post still hold true today, though some of the cleaning solvents and materials have changed. So here's how a firearm owner cleans his weapon these days:

Weapon is unloaded by the person cleaning the weapon. Person points the firearm in a safe direction, makes sure finger is far away from the trigger, magazine is removed and he/she also checks the chamber to make sure that there isn't already a cartridge in the chamber and also enables any safeties. Remember: SAFETY FIRST!
Person disassembles the firearm for cleaning, only so far as recommended by the manufacturer's manual. Typically, disassembly should only involve removing a few parts at most (field stripping). It is not necessary, for example, to disassemble the entire trigger assembly to clean a firearm. If more extensive work is required, it is probably best to consult a competent gunsmith.
After the person field strips the firearm, he or she visually inspects the parts for signs of excessive wear or damage. If any problems are seen, it is best to send it to a gunsmith immediately.
The person cleaning the firearm should have a cleaning kit available. Most commonly available kits have a cleaning rod (usually one that is disassembled into multiple parts), a few cotton cloth cleaning patches, a couple of patch holders or jags (or both jags and cloth holders) that attach to the end of the cleaning rod and to which a cloth patch is attached, a bore brush whose diameter depends on the firearm being cleaned, a hand brush, assorted solvents and gun greases and a bottle of gun oil. The user may augment this kit with extra brushes, jags, cloth holders and patches of different diameters, especially if the user owns multiple firearms of different bores. Sometimes, additional cleaning rods may also need to be purchased in appropriate diameters for different calibers.
When possible, the user always tries to clean from the breech end towards the muzzle (i.e.) following the same direction as the bullet. If it is not possible to do it in this direction (for instance, in some revolvers), then one should take precautions to not push any debris into the action of the firearm. Some cleaning kits include a muzzle guard for situations where cleaning is done from the muzzle end.
The barrel contains a couple of types of fouling: the first is due to powder residue (powder fouling) and the second is metal fouling, which is caused by metal particles from the cartridge case (brass) and metal particles from the bullet itself (lead and copper) getting deposited into the rifling grooves. There are different solvents that deal with powder fouling vs. metal fouling and some solvents (such as Hoppe's #9) do both.
The user first attaches a patch holder or a jag to the cleaning rod and attaches a cotton patch cloth at the end. The user then soaks the patch with suitable solvent and pushes it completely through the bore. This removes some of the loose powder and metal fouling in the barrel.
The user removes the patch holder and attaches the appropriately sized bore brush to the cleaning rod. Then the user soaks the brush in more solvent and pushes it through the bore again. As the user does this, the brush turns as it engages the rifling in the barrel. The user completely pushes the brush through the barrel, until the brush emerges on the other side and then pulls it back completely through and repeats the process 12-20 times. This loosens all the tiny metal particles and fouling that are stuck in the rifling grooves. It is not a good idea to reverse direction with the brush while it is still inside the barrel, because it will ruin the brush prematurely.
The user then leaves the barrel aside to soak the solvent for around 5 minutes, so that the solvent has a chance to dissolve some of the lead or carbon buildup still clinging to the barrel. In the meantime, the user grabs the hand brush (or even an ordinary toothbrush), dips it in more solvent and uses it to brush the exposed action, receiver, bolt, trigger assembly etc. and remove the gunpowder residue in here. The user then dries all the scrubbed parts with a clean dry cloth.
After the solvent has had a chance to work its magic inside the barrel, the user then takes the cleaning rod and attaches a cloth holder or a jag tip to the end and attaches a clean dry patch on it. The user then pushes it through the barrel completely. Most likely, this patch will come out very dirty. The user then replaces the patch with a new clean one and then repeats the process again for a few times, until the patch comes out looking relatively clean.
The user then applies a few drops rust-preventative to a clean cloth patch and runs it down the barrel again. This leaves a very thin coating of rust preventative solution in the barrel bore, The user may also apply this to the outside of the barrel as well.
The user then applies a very little amount of gun oil to lubricate the metal parts recommended in the manual. It is not a good idea to use too much gun oil for guns with wood stocks, as the excess oil could soak into the wood stock and ruin it (gun oil is very different from linseed oil and has a detrimental effect on wood). Excess oil also collects dust and dirt much easier, so it is a good idea to apply very little gun oil indeed, unless the gun is intended to be stored away for a while.
For the same reason, it is not a good idea to put solvent or lubricant inside the magazine because the excess gun oil will collect dirt and dust in the magazine, while solvent will react with the cartridge casings and primer and degrade them. Magazines should only be cleaned with dry brushes if needed.
Finally, the user uses a small flash light to look up through the barrel to make sure it looks clean.
The user then reassembles the firearm and uses a silicone cloth to wipe away any finger prints.

Instead of a cleaning rod, some people use a bore snake instead. This is a long flexible cord with a section of brushes and cotton cloth on one end. The user merely drops the cord through the barrel and pulls it through to the other end. A couple of runs of this and the barrel is clean and ready to go.

Lastly, before we leave, here's a few videos that demonstrate what we just discussed above:

Happy viewing!

Cleaning Firearms: A Historical Perspective

2011-08-08T00:38:00.000-07:00

In our discussion about carrying conditions a little while ago, it was mentioned that condition 4 is generally used by people who plan to store their firearms for a long while in a gun vault or safe (say, at the end of the hunting season). Which brings up a side topic -- the user also cleans their firearms before putting them into storage. This inspired the next series of articles which are going to deal with the subject of cleaning firearms.

First, we will look at some instructions for sportsmen, reproduced from W.W. Greener's book The Gun and its Development, Ninth Edition from 1910. Bear in mind that this was written for the English sportsman of the early 1900s. So while some of the cleaning equipment and solvents may appear to be a bit antiquated, these were possibly the best available from around 1850 to the early 1900s. The instructions proceed as follows:

To clean a gun after a day's shooting. If a gun be wet, it should be wiped dry at once, but the cleaning of the barrels and breech-action may be left until the sportsman or his servant has time to do it properly.

To clean the barrels. Use the cleaning-rod, with tow and oil, or turpentine. To remove the fouling, put muzzles on a piece of wood, and push the rod down to within an inch of the muzzle, and draw up to the chamber. Do this two or three times; and push right through. Use the bristle brush, or the rod with plenty of flannel; finish with the mop soaked in refined neatsfoot, pure Arctic sperm oil, or vaseline.

Never half-clean the barrels; always wipe them dry and clean before finally oiling, and do not put the mop used for oiling into a foul barrel. To remove leading from the inside of a gun barrel, soak well with turpentine; then clean well with a bristle brush, or even with a wire brush, but never use emery if the shooting qualities of the gun are valued.

Always wipe the bed, face, and joint of the breech-action with an oily rag or flannel. A little linseed oil may be rubbed over the stock occasionally.

Before putting the gun together, ascertain that all the bearing parts are free from dust and grit.

The joint may be lubricated with a mixture of half best Russian tallow and half petroleum. In most hammerless guns, if the cover plate underneath the breech-action body is taken off, the locks may be inspected, oiled, and any rust or clogged oil and dust removed from the bent.

The cocking-lifters of hammerless guns, the holding-down and top bolts, and the triggers, if they have a tendency to clog, may be touched up with a knitting-needle dipped in petroleum. They must be lubricated, whenever they require it, with chronometer oil, Rangoon oil, or finest neatsfoot.

Do not use a feather for the purpose of putting on any lubricant; a wire knitting-needle or bodkin is much better.

To remove rust from the inside or outside of a barrel, procure a tub, and with a kettle of boiling water well scald the barrels inside and out, inserting a wooden peg in one of the barrels to hold them by, wipe perfectly dry with flannel, and then oil. It is as well to do this before putting the gun aside for any length of time.

If the barrels are foul through using inferior powder, and the fouling has become hard and dry, cold water, or hot soap-suds, may be used to cleanse them. Water boiling hot kills rust.

Turpentine, often used successfully to clean the residue from gun barrels, will give great trouble if it gets into the fine-fitting parts of the mechanism of the breech-action and locks, and must therefore be used with care.

Rusty or tight breeches in muzzle-loading barrels may often be turned out, providing the breech-ends of the barrels have been soaked in petroleum, Very obstinate breeches may require to be well heated, as well as lubricated, before they can be turned out, but usually petroleum will be found a sufficient remedy for incipient rust of the working parts. All the parts of the mechanism may be cleaned with petroleum; it removes clogged vegetable and animal oils well.

So that was quite the read, wasn't it. A brief word on some of the solvents mentioned in the book:

Tallow is made by rendering the fat of beef or mutton, especially the fat found around the loins and kidneys of the animal. The process of "rendering" is as follows: raw fat is ground up and then placed in a vessel and heated with steam to drive off the moisture. As the moisture is removed, the fat is released from the fat cells. This fat is percolated off and the remaining solids are squeezed under pressure to release more fat as well (or they may be separated using a centrifuge). The tallow fat is a yellow liquid when hot, but cools down to a white creamy solid at room temperature.

Tallow being made. Note that it is currently a yellow liquid, as the tallow is still hot.

The tallow after it has cooled down to room temperature.

The tallow fat was traditionally used for soap-making, candle-making, food (it didn't spoil easily even without refrigeration), lubrication of locomotive and steamship engines etc. Russian tallow was traditionally made from mutton mainly and by the 1860s, it was cheaper to obtain in England than English-made tallow and was much more available than tallow from other British colonies such as Australia, New Zealand, the East Indies and South America. People still make tallow today, for use in food (McDonalds used tallow for cooking french fries until 1990), lubrication, high end shaving soap, shoe polish, bio-diesel etc.

Neatsfoot oil is also still around today. Like tallow, it is also made by rendering beef parts, however the parts used are only the shin bones and feet (minus the hooves) of cattle. In fact, the word neat is an old word for cattle, which is where the word neatsfoot comes from. The resulting oil is a light yellow color. Neatsfoot oil is still made today and mainly used for conditioning leather products. It is available at places like amazon.com or Walmart.

Click on image to enlarge. Public domain image.

Arctic Sperm Oil is a bit of a misnomer, as it is not actually made from the Sperm whale, but from the Northern Bottlenose whale, Hyperoodon Rostratus. This whale is a lot smaller (adult size is about 32 feet long) than the sperm whale and is found in the northern arctic waters between Europe and North America. Whalers in the 19th century found that this whale is also capable of producing oil that is very similar in chemical composition to Sperm Oil from the Sperm whale, but its oil has a more pronounced tendency to "gum" up at lower temperatures, which is why Arctic Sperm Oil was always sold cheaper than the true Sperm Oil. Because the two oils could not be told apart easily, some unscrupulous producers of Sperm Oil would sometimes adulterate their product with the cheaper Arctic Sperm Oil. Note that while both Sperm Oil and Arctic Sperm Oil were used as lubricants, but Mr. Greener appears to be recommending the cheaper of the two. Both oils were used for oil lamps and candle production, but were gradually replaced by cheaper petroleum products starting in the 1850s. However, they were still used as lubricants well into the 1960s. As of the late 1960s and 1970s, due to whaling restrictions, neither oil is available in the market these days. Animal conservationists will be happy to note that the Northern Bottlenose whale species is thriving again and the species population status is classified as "least concern". Sperm whales are also on the path to recovery and are now classified as "vulnerable" rather than "endangered".

Chronometer oil was made from extracting the oil from the head and jaws of the porpoise family (i.e.) porpoises, pilot whales, killer whales, pilot whales etc., in a very similar process to extracting the oil from sperm whales and bottlenose whales. It was used to lubricate the working parts of fine watches and ships' chronometers. As with sperm oil, it is no longer used and is replaced by other alternatives.

Petroleum is also mentioned. Petroleum was known about 4000 years ago, chiefly because it was available from natural oil springs in the Middle East. By the 1850s, the process of refining petroleum to produce kerosene was invented and drilling started soon after. However, petroleum refining really took off only after automobiles became popular. Before then (as in the early 1900s), it was possible to buy raw petroleum as the local chemists.

Linseed oil is made by pressing seeds of the flax plant. The oil is edible, but it is mainly used in paints, as a hardener for putty, in the manufacture of linoleum and as a wood finish. Linseed oil was traditionally used to finish wood gun stocks for centuries and it still continues to be used for that purpose.

Rangoon oil is actually a heavy petroleum distillate roughly along the lines of kerosene and fuel oil. It has a slow evaporation rate and was used as a rust preventative by the British around the 1850s. They found that it worked rather well, especially in hot and steaming jungles. The name comes from the fact that the first source was from a natural oil well found in Rangoon (now Yangoon), Burma (now Myanmar).

Rangoon oil may still be purchased today, especially from dealers who deal with antique and fine custom-made firearms.

Safety Mechanisms: Carry Conditions

2011-08-02T00:06:00.000-07:00

With all the discussion about safety mechanisms in the previous few posts, it is now time to discuss the subject of carry conditions, i.e. how to carry a firearm in various conditions of readiness. The various carry conditions were defined by the legendary Marine Lieutenant Colonel John Dean ("Jeff") Cooper, who did much to teach the modern techniques of handgun shooting.

Before discussing the various carry conditions, it must be noted that Lt. Col. Cooper was a big fan of the Colt M1911 and its variants. So when he defined his carrying conditions, it was with such a pistol in mind (i.e.) a semi-automatic with an exposed hammer. Therefore, some of the carry conditions may not apply to other firearm types. With that said, let us discuss the various carry conditions (from safest to readiest) and where they are used:

Condition 4: This is the safest of the carry conditions. In this condition, the firearm is completely unloaded. There is no cartridge in the chamber and the magazine is removed from the firearm. The hammer is lowered as well. Also, all safety devices on the firearm are turned on. In this condition, it will take a while to get the firearm ready to fire, because the user needs to load a magazine, insert it into the pistol, feed the first round into the firing chamber by operating the slide (which also cocks the hammer in pistols), disable all safety devices and then pull the trigger. Many people put their firearms in this condition, when they intend to store it for a long while in a gun vault (say at the end of hunting season).

Condition 3: In this condition, there is a fully loaded magazine inserted into the weapon, but there is no round in the firing chamber. The hammer is also down and all safety devices on the firearm are enabled. In this condition, the user needs to pull back the slide to feed the first round into the pistol's firing chamber (which also cocks it) and then disable all safety devices and then pull the trigger to fire. In case of a shotgun or a bolt action rifle, the user pulls on the lever to load the first round and cock the weapon. This is the condition that many people preferred to carry single or double action revolvers in, back in the day when there were no other safety devices on them. The revolver is loaded in all chambers, except for the one that is rotated to be directly under the hammer. Any unintentional impact on the hammer will not do any harm because the chamber under the hammer is empty. When the user intends to use the revolver, they pull the hammer back first to cock it, which automatically rotates the cylinder as well and now the next chamber with a cartridge comes under the hammer, ready to be discharged. The early Israeli weapons training in the 1940-60s also emphasized carrying firearms with no round in the chamber and hence this condition is also called the "Israeli Carry" method. The reason the Israelis taught this method is because when the new state of Israel was founded, most of its weaponry was old, second-hand goods. This meant that quite a few of their firearms had worn or malfunctioning safety devices and therefore new soldiers were taught to use condition 3 carry in order to prevent accidents. Since then, Israel has started manufacturing her own firearms and also can purchase quality firearms from other countries now, hence they no longer teach this method to new soldiers. Other people who carry in condition 3 are usually owners of older revolvers with no firing pin safety, or those who own a firearm with no external hammer (such as a Glock, Springfield XD, many pocket pistols from Browning, FN, Colt, Astra etc.) and wish to be extra safe.

Condition 2: In this condition, there is a loaded magazine inserted into the firearm and one round is loaded in the chamber already. However, the hammer is decocked. Therefore, to fire a weapon in this condition, one needs to pull the hammer back to cock it and then pull the trigger. This condition only applies to firearms with external hammers. Therefore it is not possible to carry a firearm with internal hammer (such as a Glock or a Springfield Armory XD pistol) in this condition. Also, it is recommended that the firearm have some kind of firing pin safety enabled, if carrying in this condition and preferably a decocking lever to safely decock the weapon. A double action (DA) revolver or pistol may be carried in this condition because the first pull of the trigger is much heavier (because it cocks the hammer first before firing it). Subsequent shots on a DA pistol are much easier because each shot now automatically re-cocks the pistol as well. A single action revolver with no firing pin safety (or a pistol with no firing pin safety) should never be carried in condition 2.

Condition 1: In this condition, a loaded magazine is inserted into the firearm, there is a round in the chamber and the hammer is cocked. Only the safety device(s) is enabled. This is also called the "cocked-and-locked" condition. To fire a weapon in this condition, one merely disables the safety device and then pulls the trigger. On a pistol such as a M1911, the thumb safety is enabled and the user needs to merely flick it down with the thumb and pull the trigger. This is the condition recommended for concealed carry and also recommended for use by some militaries when soldiers are travelling through a potentially hazardous zone with no visible danger apparent.

Condition 0: This is the condition where the firearm is in its most ready state. A loaded magazine is inserted into the firearm, there is a round in the chamber, the hammer is cocked and all safety devices are disabled. The user only needs to aim and pull the trigger to discharge it. This is the condition that police and soldiers carry their weapons in, if they are in a danger area with known enemies in the vicinity.

Some people consider a loaded Glock or Springfield XD pistol with no separate external safety, to be in Condition 0.5 (i.e. between conditions 0 and 1). This is because the built in safeties are enabled, but they are all connected to the trigger and once the trigger is pulled, it automatically disables all the safeties as part of the action. How this mechanism works was explained earlier in our discussion about integrated trigger safeties.

Organizations that issue M1911 style pistols usually specify the condition it is to be carried in, as part of their training doctrine.

While the carry conditions were originally written for M1911 type pistols, they generally apply to other firearms as well. While military doctrines clearly define what carry condition should be used in what situation, the same is not true in the civilian sector. Therefore, one invariably sees many arguments about which condition is best on various internet boards :).

Safety Mechanisms: Decocking Lever

2011-07-31T22:36:00.000-07:00

In this post, we will study a safety feature that is present in some semi-automatic pistols that are Double Action. Recall in our discussion about revolvers that double action firearms are generally able to operate in double action as well as single action mode (unless they are labelled DAO - Double Action Only, in which case they only operate in double action mode). In pistols of this sort, the user may manually pull back the hammer to cock it and then pull the trigger to release it (single action mode), or simply pull the trigger back, which cocks the hammer and then releases it (double action mode).

When fired in double action mode, the trigger pull is harder and longer since the trigger action needs to cock the hammer before releasing it.

In many cases, people like to carry their pistols with one round chambered, but the hammer decocked and any other safety devices may be turned on or off. The pistol is "considered safe" because it takes a longer and stronger trigger pull to cock and release the hammer, than if the hammer was cocked already and the trigger merely releases it.

So when a user wants to carry a pistol in this state, they initially insert a loaded magazine normally and then pull back on the pistol's slide to load the first round in the chamber. However, this same action also cocks the hammer. So, now the user wants to decock the hammer without firing the pistol. In olden days, the trick was to hold the hammer's spur down with the thumb and then pull on the trigger and then slowly let down the hammer so that it falls back to the "safe" position without discharging the loaded cartridge. Of course, this approach has some danger in that if the user's thumb slips off the hammer's spur, it could cause the hammer to strike the cartridge with force and discharge it. In order to reduce this danger, a decocking lever was introduced.

With a decocking lever, the mechanism either blocks the hammer from slamming on the firing mechanism, or by covering or retracting the firing pin out of the way, so that the hammer can be safely released without triggering the firearm. Of course, all mechanisms can fail, so it is still a good idea to point the firearm in a safe direction before operating the decocker lever.

Decocking mechanisms are found on pistols from many manufacturers: Heckler & Koch, the Sig Sauer pistol family, Walther pistols etc.

Safety Mechanisms: Drop Safety

2011-07-28T23:58:00.000-07:00

In our last post, we studied a Glock pistol for its integrated trigger safety, but we also noted that the Glock feature two additional safeties, that guard against discharge if the firearm is accidentally dropped. We will study more about those mechanisms in this post.

Mechanisms that prevent the firearm from going off when dropped or roughly handled, fall under the class of Drop Safety. These safeties work by providing an obstruction between the firing mechanism and the cartridge and are connected to the trigger. As the trigger is being pulled, these safety devices are deactivated one after other with the trigger movement. Therefore, if the firearm is accidentally dropped, the drop safety devices are all active since no one is pulling the trigger. Hopefully they work and therefore stop the firearm from going off accidentally.

The first drop safety we will study is something we mentioned in the previous article, a firing pin block safety. This is a mechanism that sits in the path between the firing pin and the cartridge primer and prevents the firing pin from striking the cartridge, when it is active. The firing pin block is connected to the trigger and as the trigger is pulled back, the firing pin block moves out the path between the firing pin and cartridge, just before the hammer is released. The hammer then strikes the back of the firing pin and the front of the firing pin can now freely strike the base of the cartridge, since the firing pin block is now out of the way. When the trigger is released, the firing pin block moves back into place again and blocks the firing pin from striking the cartridge.

The next drop safety mechanism we will study is the hammer block. The concept is very similar to the firing pin block, except that in the case of the hammer block, the mechanism sits in between the hammer and the back of the firing pin. So when it is active, the hammer cannot strike the back of the firing pin. Like the firing pin block safety, this mechanism is also connected to the trigger and the hammer block moves out of the way as the trigger is pulled.

The next drop safety mechanism we will study is the transfer bar, which is used in revolvers. In this case, the hammer does not directly strike the cartridge. Instead, there is a transfer bar that has a firing pin attached on the other end, which contacts the cartridge. When the firearm is not in use, the transfer bar is moved out of the way between the hammer and the cartridge (which is the opposite of the other mechanisms we have seen so far.). So if the firearm is dropped accidentally and the hammer releases due to impact, the hammer still won't contact the cartridge When the trigger is pulled, the transfer bar is moved into position just before the hammer is released. The hammer now strikes the transfer bar and the other end of the transfer bar which is connected to the firing pin then strikes the cartridge and discharges the firearm.

The last drop safety mechanism we will study is the oldest one: the safety notch. Unlike all the others that we've studied so far, this is a feature that needs to be engaged by the user manually. This type is used by old revolvers, lever action rifles, some old semi-automatic pistols etc. The safety notch is a cut made to the tumbler and connected to the hammer. If it is engaged, the hammer is caught before it can strike the firing pin. Therefore, if the weapon was fully cocked and if the safety was turned on, even if an accidental drop releases the hammer, it is caught at a half-cocked point by the safety mechanism.

In many areas, the law now requires that all new firearms have at least one form of drop safety on them. Many pistols have more than one drop safety mechanism, so that if one of them is worn out, one of the others will hopefully work and prevent the pistol from accidentally discharging.

Safety Mechanisms: Integrated Trigger Safety

2011-07-27T00:44:00.000-07:00

In our last post, we looked at Grip Safety Devices. In this post, we will look at something similar, the Integrated Trigger Safety device. This device really became popular because of Glock pistols, and other manufacturers such as Springfield Armory and Smith & Wesson also offer some models with this feature.

Public domain image. Click on image to enlarge.

The above image shows a typical Glock 17 Generation 2 pistol. If you were to click on the image to enlarge it, pay attention to the trigger assembly and notice that it seems a little thicker towards the bottom. That is because the trigger has a small spring loaded lever embedded into the lower half of the trigger. This is the integrated trigger safety device.

Similar to the grip safety, this spring loaded lever is automatically depressed by the user as a natural consequence of the user's actions, in this case, pulling the trigger. When the lever is depressed, it unlocks the main trigger and allows it to move. One cannot move the main trigger without depressing the small lever fully.

There are two additional safety devices built into Glock pistol models, which are also activated and deactivated by the trigger movement. One of these devices is a drop safety device. This guides the trigger bar in a ramp and it only releases by the rear-ward movement of the trigger. The other device is a firing pin safety, which is a small steel pin that sits in between the firing pin and the cartridge. The firing pin cannot strike the cartridge primer with the steel pin in the way. This steel firing pin safety device only drops out of the way, when the trigger is pulled. These devices get deactivated as a natural consequence of the trigger being pulled and are reactivated when the trigger is released.

Therefore, if the user were to drop the pistol accidentally, the safety devices would automatically activate and hopefully prevent the firearm from discharging. This design found widespread popularity among many users, who prefer not to move any manual lever or button to activate and deactivate the safety. The firearm still goes bang when the user pulls the trigger, but not if it were to be accidentally dropped.

Since Glock pistols became very popular, some other manufacturers took notice and used a similar feature in some of their products.

Safety Mechanisms: Grip safety

2011-07-24T23:32:00.000-07:00

In the last couple of posts, we studied the basics of firearm safety mechanisms as well as some manual safety mechanisms. In this post, we will study a particular type of safety mechanism called the Grip Safety. This is a popular mechanism that was first seen on the classic John Browning designed Colt M1911 pistol and later seen on other pistol models as well. It is also found in the Israeli Uzi submachine gun.

Like the name implies, a grip safety device is a lever located in the grip of the firearm. The user's hand naturally depresses the safety lever when he or she grips the firearm and this disables the safety device, thus enabling the user to pull the trigger and operate the firearm. When the user releases their grip on the firearm, the safety lever automatically pops out again and is re-enabled.

Public domain image. Click on image to enlarge.

The above image shows a Colt M1911A1 pistol. The grip safety lever is at the back of the hand grip and is automatically depressed when the user holds the pistol. There is also a manual safety lever on the firearm, at the rear of the slide, which you ought to be able to spot easily, if you've read the previous post.

Believe it or not, the original John Browning design didn't actually have a safety device, but the US Army insisted on adding a grip safety and a manual safety for the original M1911 pistol design, before they would accept it. Hence, John Browning added them for the M1911, which stayed in service from 1911-1924. The changes made to the M1911A1 model (which has been manufactured from 1924 to the present day) were relatively minor: Longer grip, wider front sight, shorter spur on the hammer etc., so it still has a grip safety and manual safety.

Public domain image. Click on image to enlarge.

The firearm depicted above is the Israeli made Uzi submachine gun. The grip safety is labelled in the above image and is pretty easy to see.

The nice thing about this design is that it is automatically enabled or disabled as the user holds or releases the firearm's grips. Therefore, a firearm with this safety device will only fire if the user is actually holding the firearm and intending to discharge it. Thus, if the user were to accidentally drop the firearm, the safety automatically enables and prevents the firearm from discharging accidentally.

Safety Mechanisms: Manual Safeties

2011-07-24T01:09:00.000-07:00

In our last post, we saw some of the basic types of firearms safety mechanisms. We will now study one type, the manual or external safety.

When set to the "safe" position, such mechanisms either prevent the trigger from moving or prevent the firing mechanism from moving or disconnect the trigger from the firing mechanism (or a combination of any of the above). Since these mechanisms typically fiddle with the working of the firearm action, the levers or buttons to activate/deactivate them are typically found close to the action as well.

There are various types of these manual safeties, such as sliding lever safety, cross bolt safety (a.k.a button safety), thumb safety etc. We will look at some of these types below.

Sliding safety or Tang safety

In the above image, we see a sliding safety lever. The lever A is a rotating lever that is rotated to lock or release the barrels from the closed state. However, lever A is not the safety. If you look behind the lever A, there is a sliding switch B, which is the safety. When set to safe, the trigger cannot be pulled.

Cross bolt or Button safety

The next type of safety is typically seen in rifles and shotguns. It is a cross-bolt or button safety. The safety is the large button labelled A right behind the trigger in the image above. When the safety is activated, it prevents the trigger from moving.

Safety/Selector lever on an AK. Click on image to enlarge.

The above image shows a selector switch/safety of an AK type firearm. The long selector lever is labelled as A in the image above. When the lever is rotated to the safe position, as in the image above, it not only locks the trigger, but also physically prevents the bolt from moving backwards fully. When rotated to either the single shot or auto-fire mode, the bolt is free to move backwards all the way

Pivot Safety

The next type of safety we will look at is the Pivot safety, where the safety lever moves about a pivot point. The above particular example also falls under the class of "thumb safety". These are typically manipulated by using the thumb to manipulate the lever, hence the name. In the above image, the lever labelled A is the pivot safety. These are common on many pistols. They work by preventing the hammer from striking the firing pin and many also disengage the trigger from the rest of the action. Some of them also serve as decocking levers, i.e. the hammer may be dropped safely so that the weapon is no longer cocked. In many pistols, there is also a corresponding lever on the other side of the slide, so that the safety can be manipulated equally easily by either a left-handed or right-handed shooter.

Click on image to enlarge.

In the above example, we see another "thumb safety" type on the pistol, but this one is a sliding button type. You can see the button directly under the red dot on the slide. Like the other thumb safety we saw above, this pistol also has another button on the other side as well, so it can be used by left or right handed shooters. Actually, this pistol has two other safety mechanisms as well, a trigger safety (note the double-trigger mechanism, the first one is a trigger safety) and a grip safety as well. We will discuss these safeties in later posts.

It must be remembered that preventing the trigger from moving only is sometimes not enough to ensure safety, as a sudden blow to the firearm in the right spot can still release the firing mechanism. Hence it is better to have a mechanism that prevents the firing mechanism from moving as well.

Safety Mechanisms

2011-07-19T23:34:00.000-07:00

In the next series of blog posts, we will look into a very important topic: firearms safety mechanisms. So what is a firearms safety mechanism and why do we need them? Well, a firearm is a weapon and we do not wish to use a firearm unless absolutely necessary, for obvious reasons. Therefore, there must be some mechanism or mechanisms that protect a firearm from accidental discharge, for example, if it were to be accidentally dropped, or if the firearm was hit by a rock or a ball or some such flying object.

The first way to do this is to carry a firearm in such a manner that it is loaded, but the user must perform an additional action before the firearm can be discharged. For example, with revolvers, people generally carry them with all but one of the chambers loaded. The lone chamber that is left unloaded is then rotated so that it is directly under the hammer and the revolver is also left uncocked. So, if the revolver were a six-shooter, the user loads five out of six chambers in the cylinder and then rotates the cylinder so that the empty chamber is the one that the revolver's hammer is directly pointing at. Therefore, if the hammer is accidentally struck, it only falls on an empty chamber. To deliberately discharge the firearm, the user needs to pull the hammer back fully with his thumb (assuming a single action revolver), which cocks the hammer and also rotates the cylinder so that the hammer will now fall on a loaded chamber. For a double action revolver, the user pulls back the trigger fully. Since it is acting in double action mode, the revolver trigger pull is much heavier and the trigger pull simultaneously cocks the hammer, rotates the cylinder to the next chamber and then releases the hammer. While this technique is actually a "policy", not a "mechanism", on many revolvers (especially older ones), this is often the only "safety mechanism" that users have.

Similarly, for modern pistols, shotguns and semi-automatic and automatic rifles, users may simply fill the magazine with cartridges and load it in, but carry the firearm without a cartridge in the firing chamber. To discharge the firearm, the user needs to hold the firearm with one hand and use the other hand to pull back on the slide (or lever in case of some shotguns or rifles) to cock the weapon and also load the first cartridge from the magazine into the firing chamber. Then the user can pull the trigger to discharge the firearm. Therefore, it takes a conscious pair of actions before the firearm is made ready to fire and it cannot be discharged unintentionally, if say, it were accidentally dropped on the hammer. This method is sometimes called the "Israeli Carry" method in the US and Canada. The origin of this term is because in the early days of the IDF (Israeli Defense Force) history, they had severe budget constraints and were forced to acquire large numbers of antiquated firearms with questionable mechanical safety mechanisms. Therefore, the early IDF personnel were taught to carry with the chamber empty and hammer down.

Of course, quite a few people like to carry their firearms loaded and cocked, with one cartridge already in the chamber (called the "+1 carry method" i.e. magazine fully loaded + 1 extra loaded in the chamber), because they do not like the idea of spending extra time to prepare the weapon for firing, which may cost one's life. Also, there may be a chance that the user may drop the weapon after they have begun firing. Obviously, there needs to be safety mechanisms to protect against these situations as well. These are the mechanical safety mechanisms we will study in the next few posts.

Safeties can be divided into two major types:

External or manual safety: These typically consist of mechanisms which explicitly require the user to switch them on or off separately. For example, there may be a safety lever or button that needs to be pushed to turn the safety mechanism off.
Internal or automatic safety: These are typically turned on or off as part of another action. For instance, many modern firearms have a hammer block that prevents the hammer from striking the firing pin. Only when the trigger is pulled is the hammer block moved out of the way of the hammer's path. Therefore, the act of pulling the trigger deactivates the internal safety and the hammer will not strike the firing pin if the firearm is accidentally dropped.

Many modern firearms come with a mixture of both types of safeties. We will look into various safety mechanisms in the next few posts.

As might be noted, the argument about carrying a firearm with the chamber loaded or not is an ongoing one. Some argue that it takes too long to load a cartridge into the chamber, while others say it doesn't take that much extra time. Others argue that in a stressful situation, one may forget to load the weapon. Also the user may not have both hands free to do this. These days, with access to better firearms, the Israelis have even stopped teaching the so-called "Israeli carry" method for the last 20 years or so. The following pair of videos shows both techniques:

Night Vision Devices

2011-07-08T00:16:00.000-07:00

In this post, we will look into a special form of sights, the Night Vision Device. These allow the user to operate in darkness and low light conditions.

The origin of night vision devices traces back to a bit before World War II broke out. The American RCA company and the German company AEG Telefunken were the pioneers in this field in the mid-1930s. The first generation of these devices (often referred to as "Generation-0") were of the "active" type. What this means is that these devices work by projecting infrared light upon a target and then making an image intensifier that is sensitive to light at these frequencies. The image intensifier uses a vacuum tube to accelerate electrons reflected from the IR beam on the target, between the anode and photo cathode of the tube. The accelerated energy charge strikes a phosphor screen (like a TV screen) where the image is focused and can be viewed via an eyepiece. Since human beings cannot see infrared light, they are unaware that they are being targeted in the dark. The first such devices were designed to be used by snipers. Many of these Gen-0 devices had pretty abysmal sensitivity and were sometimes worse than an unaided human eye. Another major problem with these devices was that the enemy troops could also wear night vision goggles and immediately detect where the sniper was hiding. The image intensifiers used vacuum tube technology and therefore, used large amounts of electricity. The use of vacuum tubes also distorted the returned images quite a lot. Vacuum tubes also had a shorter life and would often stop working in the field. The infrared illuminators were also pretty massive and often had to be mounted to a flat-bed truck. Despite these disadvantages, Gen-0 devices saw use in World War II and the Korean conflict.

The next generation devices ("Gen-1") saw action during the Vietnam War in the 1960s. Unlike Gen-0 devices, these were designed to be "passive" type devices (i.e.) they do not require their own source of infrared light and can work under moonlight conditions.

Generation 1 Night Vision Device AN/PVS-2 mounted on M16 assault rifle. Click on image to enlarge. Public domain image.

In the above image, we see a typical Generation 1 device from the Vietnam war era, mounted on top of an M16 A1 rifle. The device in question in an AN/PVS-2 Starlight scope. The device is still pretty bulky, but it doesn't need a separate IR projector. The image intensifier technology still used vacuum tube technology and still had image distortion problems. To improve the gain on these devices, multiple vacuum tubes were often cascaded together, making the image amplification to the order of 1000x to 2000x and having a service life of around 2000 hours. Despite that, these devices only worked well during full moon conditions and could not be used in anything less than half-moon conditions, which means they were pretty much useless during half the month and also on cloudy nights.

The next generation of devices ("Generation 2") came out in the 1970s. Due to major improvements in tube technology, Generation 2 devices offer much less distortion of the image and more reliability than Generation 1 devices. Gen-2 devices use microchannel plates instead of cascading vacuum tubes in the image intensifier. This makes them much more sensitive to IR light than Gen-1 devices and they can be used effectively even on moonless nights and in fog and cloudy conditions. The use of microchannel plates means that the viewed image often has a distinct square or hexagonal pattern on it. Compared to Gen-1 devices, these typically offer up to 20,000x to 30,000x amplification and last about 2500 to 4000 hours. Examples of such devices include the AN/PVS-4 and AN/PVS-5.

A soldier using an AN/PVS-4 night vision device.

Gen-2 was followed by an improved Gen-2+, which offers better performance during high and low light levels. In fact, Gen-2 devices may still be found on sale in the market today.

The next generation (Generation-3) of devices has no change in the basic technology of Generation 2 devices, but the components themselves have improved, thereby contributing to better resolution and longer life. For one thing, the photo cathode uses Gallium Arsenide (GaAs), which makes it much more efficient than the older technologies. The microchannel plate is also coated with an ion barrier film, thereby increasing the life of the device. Gen-3 devices offer 30,000x to 50,000x amplification and last about 10,000 hours or so. The first Gen-3 device was the AN/PVS-7 which was originally fielded in limited numbers in 1988 to military personnel in Fort Hood. This was followed by AN/PVS-10 and AN/PVS-14 in the 1990s and Gen-3 devices are still in use with the US military. In fact, they saw widespread use in Operation Desert Storm in the 1990s, where they certainly proved their worth.

During all this time, night vision devices were mainly used by military forces because of high prices and lack of accessibility in the civilian market. That all changed during the early 1990s, due to the collapse of the former Soviet Union. A number of Gen-0 and Gen-1 devices from Soviet military surplus became available in the western civilian market and caused an overall drop in the prices of night vision devices and they became much more accessible to civilians as well. These days, one may find Gen 2, Gen 2+ and Gen 3 devices available for sale to civilians.

Generation-4 devices are currently under development. Among the planned improvements is an automatic gated power system, which allows quick switching on and off of the photo cathode. This allows the user to move from a well lit to a dark environment or vice-versa easily.

One question that puzzles many people is why does the image of a night vision device show up in green? There is actually a very good reason for this. Apparently, the phosphor screen is deliberately coated green because it turns out that the human eye can distinguish between more shades of green than any other color.

Flash Suppressor a.k.a Flash Hider

2011-07-07T00:08:00.000-07:00

In our last couple of posts, we studied the topic of suppressors (a.k.a. silencers). In this post, we will study a related family of devices, the flash suppressor a.k.a flash hider. In our study of silencers, the main purpose of those is to reduce the sound level of the firearm to make it more comfortable for the user to use it. As was noted previously, many silencers also reduce the amount of flash coming out of the weapon as well.

A flash suppressor (a.k.a) flash hider is not designed to remove any sound from the firearm. Instead, its sole purpose is to reduce the flash from the muzzle. So what is muzzle flash and why do we need to get rid of it. Basically, when a firearm is fired, the cartridge propellant burns inside the barrel and pushes the bullet out. If the barrel is a little too short or if the quantity of propellant is a bit too much, some of the propellant particles end up burning outside the barrel and thereby creating a huge fireball in front of the gun. The sudden bright flash may cause the user to be temporarily blinded, especially during night time. This was not so much a problem in previous centuries, when firearms had really long barrels and propellants had plenty of time to burn completely inside the barrel. With newer powders and modern assault rifles having much shorter barrels than previous firearms, it became much more of a common occurrence. Carbines also experience this problem due to having shorter barrels than normal rifles.

A flash suppressor works in a couple of ways. First, it can redirect the exiting gases to exit via the sides of the barrel instead of in all directions, thereby keeping the shooter's vision at the top of the barrel unaffected. Second, it allows the exiting gases to expand rapidly, which cools them off and reduces their temperature, which also reduces or eliminates the brightness of the flash.

The earliest type of flash suppressor came out around World War II and is called the cone suppressor or cone flash hider. This was introduced with the Lee Enfield carbine model V. They may still be seen these days on some AK models.

A cone flash suppressor which is normally used with AKs

An AK weapon with attached cone flash hider

In the above pictures, we see a shortened AKS-74 with a cone style flash hider. It is a screw on type, which may be attached to the end of an appropriately threaded barrel. Note the hole on top in the first picture. When screwed on, this hole serves to redirect some gases up and acts as a brake to reduce the muzzle climb as well.

The next type of flash hider we will study is the duckbill type, which was often seen on early M16 models used in Vietnam. This consists of a device with a number of prongs on it, such as the image below:

A duckbill type flash suppressor

Early M16 A1 model with duckbill flash suppressor attached. Click on image to enlarge.

As can be seen by the image above, the flattened prongs tend to resemble the bill (beak) of a duck, which gives this device its name. The prongs serve to redirect the gases to the sides, but not to the top of the barrel, so any flash that is generated will not go in that direction. While these were more effective than the earlier cone models, the prongs tended to get fouled up with vegetation when fighting in the jungle. The prongs also have a chance of getting bent on the open end, due to rough usage in the field. This doesn't mean that open-type flash hiders like this are obsolete. Some modern weapons, such as the Heckler & Koch G36 series still use them.

The problems experienced with the duckbill type flash suppressor led to the development of the birdcage type of flash suppressor. This is similar to the duckbill type, but also has a ring in front of the flash suppressor.

Birdcage type flash suppressor.

The ring in front supports the prongs and also prevents branches, grass and other vegetation from easily entering into the prongs. This type of flash suppressor came standard with the M16 A2 model. Also, in the M16A2, the flash suppressor not only prevents gas escaping from the top, the bottom is closed off as well. This prevents the hot gases from kicking up sand and dust when the shooter is firing from the prone position. This type is seen on many weapons today , including AKs, SIG, M16 etc.

Suppressors a.k.a Silencers - Part II

2011-07-03T20:59:00.000-07:00

In our previous post, we studied some basics of suppressor technology. We will now study them in a bit more detail.

As we noted in the previous post, the way that suppressors work is by slowing the expanding propellant gases by trapping them in chambers and allowing them to expand and cool a bit, which causes them to escape out of the muzzle at a lower pressure and velocity than if the suppressor was not present.

There are two basic types of suppressor (a) the screw-on type (a.k.a can type or muzzle type), where a suppressor is simply screwed on to the end of the muzzle when required and (b) the integral type (a.k.a Reflex suppressor), where the suppressor is designed as part of the barrel. The screw-on type suppressor is often a third party attachment and not designed by the manufacturer of the firearm. It can be screwed-on or removed as desired by the user and can also be used on other firearms as well, provided they are all of the same or smaller caliber. Firearms typically need to be modified to add a screw thread on the outside of the barrel in order to screw on the screw-on type suppressor. Contrast this with the integral type suppressor, which is designed by the firearm manufacturer from the very beginning as part of the firearm. With this type, the barrel is enclosed by the suppressor along its length and the barrel is drilled in several places to allow the expanding propellant gases to bleed off into the enclosing suppressor. Since the integral suppressor encloses the barrel, this makes the overall weapon length shorter than if one was using a can-type suppressor.

Even though suppressors work by slowing down the exit gases, well designed ones do not affect the exit velocity of the bullet that much. In addition, many of them also reduce the flash and recoil of the firearm as well. The expanding gases do contribute to wear and tear on the internals of the suppressor. Depending on the type and materials used in constructing the device, the wear rates can greatly vary. Cheap ones can last between 15-20 shots, whereas a good one could easily last 30,000 shots or so.

Suppressors a.k.a Silencers - Part I

2011-05-29T23:51:00.000-07:00

A suppressor (or a "silencer") is a device that is screwed on to the barrel of a gun and designed to reduce the amount of noise and flash generated by a weapon. Before we start to study about these devices, it is good to clear up a few myths about them (and these myths are mainly due to Hollywood movies). The biggest myth is that they make a firearm almost noiseless -- you only hear a soft "phut" noise, if all the James Bond movies are to be believed. The second biggest myth is that in the absence of a suppressor, you can improvise with almost any cylindrical object (bottle filled with water, coke can etc.)

The first thing to note is that there are multiple sources of noise possible from a firearm:

Noise of the hammer striking the cartridge.
Noise due to the exploding propellant material and hot gases leaving the barrel.
Noise due to the bullet flying through the air (sonic boom, if the bullet is flying supersonic).
Noise due to ejecting the empty cartridge case and cocking the weapon.
Noise due to bullet striking the target.

Of all these sources, #2 and #3 are the main sources of loud noise from a firearm. Let us consider the noise from #2 (i.e. exploding propellant material). This typically hits about 140-160 dB, which is louder than your average heavy metal concert (trust me on this one, I've attended quite a few of them). No suppressor is going to remove such a loud noise like this completely. At the most, a suppressor drops the sound level to around 130-145 dB, with the quietest ones measuring about 117 dB, which is still in heavy metal concert territory. So, what's the use of such a device if it doesn't remove the sound completely. Well, when hearing protection is added, this makes the loudness level easier to bear. These devices also remove the flash emanating from the barrel and thus make it less likely to disorient shooters. They also change the sound signature of a firearm, so that the sound doesn't exactly sound like a shot. As the old Finnish expression goes, "A silencer does not make a marksman silent, but it makes him invisible". You can observe how the sound signature changes in the below video, where the person fires a 9 mm. pistol, first with no suppressor and then with a suppressor screwed on:

As you may note, the suppressor doesn't completely remove all the noise, but it does remove a fair amount and also the sound no longer sounds like a gunshot.

There were many inventors of silencing devices towards the end of the 19th century, with one patent granted to J. Borrensen and S. Sigbjornsen for a device that "lessens the sound of discharge" in 1899. However, the earliest successful commercial suppressor was invented in 1908 by the American inventor, Hiram Percy Maxim, the son of Sir Hiram Stevens Maxim, the man who invented the first portable automatic machine gun. His device consists of a hollow cylindrical tube with a number of expansion chambers in it.

This device is screwed on to the end of the barrel. Expanding gases from firing the cartridge are trapped by the baffle plates, while the bullet travels through the hole in the center. The trapped gases expand and cool and thereby exit out of the barrel with less pressure and velocity, which reduces the noise. This device was sold under the trademarked name "Maxim Silencer", which is probably why we still call suppressor devices as "silencers" even though they don't actually silence a firearm completely.

Mr. Hiram P. Maxim also had interests in the emerging automobile industry and he developed a similar device to reduce engine noise, which we still use today: the muffler, which is also known as a "silencer" in some parts of Asia and Europe.

Since these devices don't entirely remove the noise, the firearms industry prefers to call them "suppressors" instead of "silencers". In our next post, we will look into more about such devices.

What is a wildcat cartridge?

2011-05-29T10:47:00.000-07:00

A wildcat cartridge is a custom made cartridge, usually made by modifying an existing commercial cartridge, in order to optimize cartridge performance (e.g. more power, more velocity, better accuracy etc.) Since these are custom made, they are more expensive than normal cartridges. Also, wildcat cartridges are usually used mainly by very serious shooters and hand-loading fans, there is only a limited market for them and larger cartridge manufacturers generally don't make them.

In terms of variety, there are more wildcat cartridge varieties than commercial production cartridges. However, many of these varieties are produced in very small quantities indeed.

In some cases though, some cartridges started out as custom-made wildcat cartridges, but gained enough popularity that they began to be commercialized (i.e. rifles chambered for them are now available commercially) and SAAMI standards were specified for them. Examples of such cartridges are the 6.8 mm. SPC, which was originally developed in collaboration with some members of US SOCOM. The 6.8 mm SPC is based on a .30 Remington cartridge, modified to .270 caliber and then further modified in length to fit in an magazine that can be fitted into the magazine wells of the M16 rifle. Therefore, any M16 or AR15 type rifle only needs replacing of the barrel, bolt and magazine to use this new cartridge. This cartridge is more lethal than the standard NATO 5.56x45 mm. cartridge fired by the M16 and while it is not officially adopted by the military, it has found use by special forces troops in Afghanistan and Iraq and is gaining popularity as a commercial civilian round. Another example is the well-known .357 magnum cartridge developed by Smith & Wesson, which was originally developed from a .38 Special cartridge. The .357 and .38 Special cartridge are both the same diameter externally and only differ slightly in length, because of safety reasons. Early versions of .357 magnum were actually identical dimensions to .38 special cartridges and the length was only altered so that people could not accidentally load the more powerful .357 magnum cartridges into a firearm not designed for the additional pressure. Another example is the 6 mm. PPC (Palmisano & Pindel Cartridge, named after its inventors, Lou Palmisano and Ferris Pindell). This cartridge started out as an improvement of the .220 Russian cartridge, which was itself based on the venerable 7.62x39 mm. cartridge used on the AK-47 and AKM assault rifles. The 6 mm. PPC case is made by forming the .220 Russian brass case into a new shape and is specially geared for single-shot bench rest shooting. It is one of the most accurate cartridges available up to 300 yard ranges and has been produced since 1975 and used in several competitions.

As mentioned earlier, wildcat cartridges are generally used by very serious shooters mainly and quite a few require barrel modifications also in order to use the modified cartridge. The modified barrels are usually supplied by custom barrel makers, who typically work out of small shops. The custom barrel makers generally also supply the buyer with reloading tools and dies, so that buyers can make their own cartridges. Some barrel makers also supply data about how different powder brands, powder quantities and bullet weights perform with their barrels. Therefore, most wildcat cartridges are developed, either by the custom barrel makers themselves, or by someone who is working in conjunction with a custom barrel maker.

.243 Winchester Ackley Improved wildcat cartridge on the left, compared to a normal .243 Winchester cartridge on the right.

Note the reduced case taper and sharper shoulder angle in the Ackley Improved version, which leads to more case capacity and therefore, more propellant.

Image copyright Arthurh at wikipedia and licensed under the Creative Commons Attribution-Share Alike 3.0 Unported License.

There are many reasons why people develop wildcat cartridges, such as:

Increasing the case capacity (as in the Ackley Improved cartridge pictured above) allows adding more propellant to the cartridge, which increases the velocity of the bullet and therefore, the energy transferred by the bullet.
Reducing the bullet's caliber increases its velocity, thereby increasing its resistance to wind drift.
Better consistency can be achieved by tuning a bullet's diameter, weight and velocity to a particular amount and type of propellant, which leads to greater accuracy.
Feeding issues of certain types of ammunition can be fixed. For instance, it is not possible to reliably fire hollow-point bullets with .45 ACP pistol ammunition because of feeding issues from the magazine. Hence, the shape of the cylindrical cased .45 ACP cartridge was modified to a bottlenecked .45 cartridge to solve this issue.
Some shooters like to use rifle ammunition with pistols, for greater accuracy. In this case, one starts out with a rifle cartridge and then reduces its case capacity so that it can be used with a pistol.

A wildcat manufacturer generally starts out by using a commercial cartridge case and changing its shape to new dimensions. Usually, this involves pushing the shoulder of the cartridge backwards or forwards as needed to modify the case capacity and also changing the diameter and length of the cartridge neck. This process can be done by either cold forming (i.e. the case is pushed into a die and pressure is applied to change the shape of the case) or fire forming (i.e. the case is placed in a chamber of a different dimension and loaded with a light gunpowder charge. Upon firing the charge, the case takes the shape of the new chamber). Sometimes a mixture of both methods is used to make the final case shape of a wildcat cartridge. Next, the manufacturer trims the case to the appropriate length, because cold forming or fire forming generally tends to increase the length of the case's mouth and the excess length needs to be trimmed. Then the diameter of the neck is changed as needed for the new bullet. The cartridge is then hand-loaded carefully and a bullet is crimped on.

In quite a few situations, firearms can be very easily modified to use the new wildcat cartridges. For example, the Ackley Improved cartridge shown above could easily be used by rechambering an existing firearm. Better still, a firearm that is chambered for the "Improved" cartridge can also fire standard factory loaded ammunition as well, which allows the owner to use less expensive and commonly available ammunition if there is a shortage of wildcat cartridges. Ackley Improved family of cartridges were developed by Patrick Otto Ackley, a prolific gunsmith and author, who produced many improved versions of commercial cartridges in several different calibers.

History and Development of the Assault Rifle - X

2011-05-29T01:58:00.000-07:00

With the advent of bullpup designs in the 1970s such as the Austrian Steyr AUG and the French FAMAS, some of the newer designs that have emerged since then have largely been bullpup designs. Some of these include the British L85A1 and L85A2 of the 1980s, the Chinese QBZ-95, the German Heckler & Koch G11, Singapore's SAR-21, Israel's Tavor TAR-21 etc.

Since the advent of the 5.56x45 mm. NATO cartridge, the world has essentially gone into three basic calibers as far as militaries are concerned: the NATO 5.56x45 mm. (used by M16, Steyr AUG, FAMAS, L85, INSAS etc.), the Russian 5.45x45 mm. (used by AK74 family) and the Russian 7.62x39 mm. (used by AK-47, AKM and clones such as the Type 56). The first two of these are generally used by most military forces, whereas the third cartridge is generally widespread among many insurgent groups due to the popularity and wide-spread nature of the AK-47 and AKM family of assault rifles. However, there has been some other significant research in cartridge developments as well. Both the UK and the US did some work to find an intermediate cartridge between the NATO 5.56x45 mm. and the older NATO 7.62x51 mm., in order to strike a balance between bullet effectiveness and recoil force. This was due to the 7.62x51 mm. cartridge having too much power and weight and the 5.56x45 mm. not having sufficient range for some applications. Experiments showed that cartridges such as the 6x45 mm., the Grendel 6.5x38 mm. or the Remington SPC 6.8x43 mm. strike a pretty good balance by having more range than a 5.56x45 mm. cartridge, but still having relatively less recoil and less weight than a 7.62x51 mm. cartridge. With combat in Afghanistan taking place over longer ranges and the advent of scopes on assault rifles, it is possible for an infantryman to engage over longer ranges now and hence there have been noises made in various quarters to replace the M16 with a newer rifle using one of these cartridges instead.

Newer bullet designs using exotic technologies were also tried out during the 1970s and 80s, but they've been much less successful in this regard. For instance, there were attempts to design cartridges that fired flechette darts instead of conventional bullets. However, the cost of ammunition was prohibitive and thus this never became popular. Another exotic concept was folded ammunition, which was ammunition that was roughly U-shaped. The idea was to reduce the length of the cartridge in order to speed up the firing cycle of rifles.

Folded ammunition examples. Click on images to enlarge.

Folding ammunition never caught on either. Another concept was the caseless ammunition cartridge, for which a lot of work was done by Hecker & Koch and Dynamit industries. The idea is that since a caseless cartridge doesn't have a brass case, there is no need for the rifle to eject it after every shot, which reduces the number of steps in a firing cycle and thereby enables faster firing rates. H&K developed the G11 assault rifle to use caseless ammunition. The concept of a consumable cartridge is actually a very old one, as it was used by the Dreyse Needle Gun of 1835! However, with automatic weapons and modern ammunition, there are more problems to solve. For one, caseless cartridges are more easily damaged by rough handling since they don't have a hard outer case and two, the brass case removes some of the heat from the chamber of the firearm and the lack of a brass case means that caseless ammunition could cook-off in a hot chamber. H&K solved the first problem by putting cartridges in a sealed plastic case and had to spend a lot of time developing special propellants to solve the second issue. The G11 was about to be adopted by the West German military when the Berlin wall came down and the cold war ended. This resulted in cutbacks in military spending and H&K went into financial difficulties as a result and was acquired by the British, where they earned their keep by helping fix problems with the British L85 assault rifles. Interest in caseless ammunition technology has been renewed since 2004, due to the US military's Lightweight Small Arms Technology (LSAT) program.

Oddly enough, despite most of the new rifles being bullpup layouts, the US military is looking at conventional layouts for their M16 replacements. For instance, the US Army has switched to the M4 (which is the carbine form of the M16). The (now cancelled) XM8 project, which was designed to replace the M16, also had a conventional layout:

XM8 Assault Rifle. Click on image to enlarge. Public domain image.

The FN SCAR, adopted by the US Special Operations Command (SOCOM) as well as the US Marines M27 Infantry Automatic Rifle also use conventional layouts. Thus, it appears that the US is definitely not bucking the bullpup-layout trend, at least in the near future.

Another interesting concept developed in Australia is the Metal Storm rifle, where many bullets are stacked head to tail in series inside a barrel, with propellant between the bullets. Ignition of individual cartridges is accomplished electronically. Since the cartridges are completely consumable and because they are stacked one behind the other in line, there is no need for case ejection or a feed system to load new cartridges in the chamber. This makes the firing rate much faster than other designs, as well as contributing to reduced weight. As of now, Metal Storm products have found limited use and support from the US Marines.

History and Development of the Assault Rifle - IX

2011-05-16T00:09:00.000-07:00

A couple of posts ago, we saw how the US adoption of the M-16 and its 5.56x45 mm. cartridge led to the various member countries of NATO also standardizing the same caliber cartridge in their forces. Some NATO members adopted the M-16 as their standard rifle as well, whereas some others designed their own rifles to use the new NATO cartridge. One of those countries was Austria. At that time (late 1960s), the Austrians were using a variant of the FN-FAL, which used the previous NATO standard cartridge of 7.62x51 mm. The Austrian military decided to make an all new rifle design to replace their old rifles.

Design and development duties of the new rifle was handed to the Steyr-Daimler-Puch company, in collaboration with the Austrian military.The Steyr-Daimler-Puch company has a long history in Austria as a manufacturer of vehicles and firearms. In fact, when Steyr was first founded in 1864, its primary business was manufacture of rifles and they only branched out into making bicycles in 1894 and automobiles in 1915. It later merged with the well known Daimler-Puch automobile manufacturer in 1934 to become Steyr-Daimler-Puch. After World War II, the company gained some bad reputation, as it later emerged that its managing director was the first to suggest using concentration camp slave labor in their factories. However, its reputation did not suffer much after the war and it still remained a manufacturer of heavy vehicles, offroad vehicles, bicycles, small mopeds and scooters. In the US, their mopeds and scooters were sold by Sears Roebuck under the Allstate brand in the 1950s and 60s. In India, their Puch Maxi Plus moped model (made in India in collaboration with Hero Motors and sold as the Hero Puch) was in production until 2003!

During the development process of the new rifle, the Austrian military placed the Office of Military Technology under one Colonel Walter Stoll in charge of development from the military side, while three men, Horst Wesp, Karl Wagner and Karl Moser handled things from Steyr-Daimler-Puch's end. The result was the Steyr AUG rifle.

Steyr AUG Assault rifle. Click on image to enlarge.

Image licensed from Steyr Mannlicher GmbH & Co. under the Creative Commons Attribution 2.0 License.

The letters AUG stand for Armee Universal Gewehr (i.e.) Universal Army Rifle. From the beginning, the AUG was designed as a family of firearms (i.e.) a carbine, an assault rifle and a Light Machine Gun (LMG). This means that many parts between these three are interchangeable. It also was one of the first successful bullpup designs. Design of the rifle was completed in 1977 and it was accepted by the Austrian military in the same year as the StG 77 (Sturmgewehr 77). Since then, it has been adopted by various countries around the world.

While many people think that the Steyr AUG was a very revolutionary design when it first came out, a lot of the features on it existed long before the rifle was conceived. For example, the idea of a family of rifles (i.e. carbine, assault rifle and LMG) sharing many parts in common is not new. The same modular concept was already used successfully by the Soviet designer Fedorov during World War I. In fact, we studied about Fedorov's design earlier in our first installment of assault rifle development. Another misconception is that the AUG is the first bullpup design. The truth is that while it was one of the first commercially successful bullpup designs, it was not the first bullpup design and not even the first military bullpup design. The original bullpup rifle was the British Thorneycroft carbine from 1901. Additionally, the French FAMAS (also a bullpup) was also being developed at around the same time as the AUG. The use of plastics in the weapon was also not a new idea, as the Soviet-made TKB-408, which was designed by German Korobov also had plastics, as did the French FAMAS rifle. Finally, the built in telescopic sight was also not a new innovation, as it was already a feature of the British Enfield EM-2 rifle (also a bullpup design) from the 1940s and a Canadian FN FAL variant in the 1950s.

The real technical merit of the AUG is taking a group of very good ideas and combining them all into a successful design.

History and Development of the Assault Rifle - VIII

2011-05-03T22:31:00.000-07:00

In the last few posts, we saw during the development of the M-16 rifle, that the US military had determined that "small is beautiful" and therefore used smaller-caliber, but higher velocity ammunition for their assault rifles. The chief motivation for smaller ammunition was because studies had shown that the side with the most firepower tended to win infantry engagements. However, this meant that each soldier would need to carry a larger amount of ammunition, so the US decided to research smaller calibers, which are lighter and therefore a soldier can carry more of them. Research showed that 5.56x45 mm. cartridges were lethal enough at ranges where most infantry combat took place and so they developed assault rifles around this concept: the M16 family.

The results of this research did not go unnoticed by the Soviets. At that time, the Soviets were using the AKM assault rifle as the standard rifle for their military. The AKM and its predecessor, the AK-47, fire 7.62x39 mm. cartridges. In line with western findings, the Soviets also decided to develop another assault rifle, one that uses smaller bullets than the AKM or AK-47. Of course, they did not want to copy the same 5.56x45 mm. cartridge as used by the West, because the Soviets went to great pains to ensure that their own weapons could not be used against them. Hence, they designed a new cartridge of size 5.45x39 mm. and designed a new assault rifle that used the same basic mechanism as the AKM, but scaled down to use the new cartridge. Since the new rifle and cartridge were developed in 1974, the new rifle was called the AK-74. This rifle is still in use in the Russian military.

AK-74 assault Rifle. Click on image to enlarge. Public domain image.

The AK-74 is heavily based on the AKM design, so much so that about 50% of the parts (pins, screws, springs etc.) are interchangeable between the two, even though they are of different calibers. However, the AK-74 also has a bunch of other improvements over the AKM, in order to increase reliability, accuracy and durability. For one thing, the bolt extraction claw is larger on the AK-74 to better extract spent cartridges. The stock is lighter on the AK-74 and was originally made of laminated wood, with cuts on the side to save weight. The stock, pistol grip and hand guards were all later changed to a polymer. The magazine is made of a polymer plastic, unlike the metal magazines of the AKM or AK-47. The magazine also has two extra horizontal ribs in it, which make it impossible to insert it into an older AK family rifle.

Other variants of the AK-74 have folding metal stocks (AKS-74 and its carbine variant, AKS-74U)

A variant called the AK-74M does away with all the wood and the stock, pistol grip and hand guards are all black or plum colored plastic.

AK-74M assault rifle. Click on image to enlarge. Public domain image.

Note the lack of wood in the above rifle.

The AK-74M also has a mounting rail on the left to attach other hardware such as telescopes. Since the early 1990s, the AK-74M model is the current official rifle of the Russian military and is gradually replacing the older AK-74 and AKS-74 models in service.

The Russians have also designed the AK-101, AK-102, AK-103, AK-104 and AK-105 assault rifles, but these use the same AK-74 design, but are chambered for different calibers instead. For instance, AK-101 and its carbine form, the AK-102, are chambered for the NATO 5.56x45 mm. cartridges and are specially designed for the export market.

History and Development of the Assault Rifle - VII

2011-05-01T00:30:00.000-07:00

In our last post, we studied how the AR-15 rifle was morphed into the M16 A1 model. Where we last left off was during the Vietnam war.

The original design for the M16 had a number of flaws: lack of cleaning kit, no chrome lining on the inside of the barrel or chamber, issues with cartridges etc. These flaws became more evident during the Vietnam war, but sadly, only after a number of US servicemen lost their lives. Soon after a Congressional investigation, fixes were made for all these issues and the rifle became a much more reliable product. However, the bad reputation earned by its early flaws took a lot longer to clear.

By 1970 though, the M16's reputation was established and other countries also wanted their own M16 style rifles. The NATO member countries decided to standardize on the 5.56x45 mm. cartridge, which was also used by the M16 A1 model, but they wanted to make improvements to the US version of the cartridge, in particular, because of improvements to body armor technology. The US version of the 5.56x45 mm. cartridge was called the M193 and tests had shown that it didn't penetrate newer body armors that well. The British, Germans and Belgians all presented cartridges that all had the same 5.56x45 mm. external dimensions, but had different bullet shapes and materials that offered much better ballistics and penetrating power than the M193. In the end, the Belgian designed SS109 (which has a bullet with a steel tip) was chosen as the NATO standard. The Belgians also designed a tracer round, L110, which had better performance than the old M196 tracer round. The M196 could burn out in 450 meters, whereas the L110 could show its trail to 800 meters. However, it was found that the M16 A1's barrel rifling twist rate of 1/12 inch (i.e. 1 turn every 12 inches or 1 turn every 300 mm.) was not adequate to stabilize the SS109 or L110 bullets past about 90 meters or so. New barrels with a faster twist rate were required to get the best performance out of the SS109. The ideal rate for a bullet from a SS109 cartridge is at least 1 turn in 9 inches (1 turn in 229 mm.), but the L110 requires at least 1 turn in 7 inches (1 turn in 180 mm.) to continue to be stable for much longer ranges (over 800 meters or so). Hence, it was decided to make a new version of the M16, the model A2, which would feature a barrel with a 1 turn in 7 inch twist rate.

It was also found during the Vietnam war, that many soldiers would put their M16s into full-automatic mode and when in a firefight, new soldiers would often hold down the trigger and shoot entire magazines into the bushes in a few seconds, without killing a single enemy. This caused many of them to run out of ammunition prematurely. Also, the act of firing in full-automatic mode makes the rifle more difficult to control and thereby reduces accuracy. The US military conducted various tests a decided to replace the full-automatic firing mode with a three-round burst mode (i.e. upto 3 rounds would fire when the trigger is held down), because the three-round burst was determined to be the optimum balance between accuracy, ammunition conservation and firepower. The US Marines were the first to request the development of the M16A2 model based on the Vietnam war experiences.

M16A2 model. Click on image to enlarge. Public domain image.

Along with the newer barrel with the 1:7 inch twist rate and the three-round burst mode, there were numerous other improvements made to the M16A2. The thickness of the barrel in front of the front sight was made thicker, to avoid bending the barrel in the field and to also resist overheating better, thereby allowing firing the weapon for longer periods of time. The front and rear sights were improved and the rear sight was made adjustable for ranges between 300-800 meters using the SS109 cartridge (which had different ballistics than the M193). The recoil compensator at the end of the barrel was closed at the bottom, so it would not kick up dust when fired in the prone position. A deflector was attached immediately behind the ejection port, so that left handed users would not get hit in the face by a hot ejected case. The grips were improved and the handguards were made symmetrical so that there was no need to manufacture spare parts for left and right side. With advances made in polymers, the buttstock was re-engineered to use a new plastic that is 10 times stronger than the original stock on the M16A1. The buttstock was also made slightly longer than the original version.

The M16A2 model was first adopted by the US Marine Corps in 1982, followed by the US Army in 1986 and then the other branches of the US military, as well as military forces of other countries worldwide. It is still being used by many users and is the most common variant in the M16 family.

The M16A3 model came out around the same time as the M16A2, but was made in very small numbers indeed. The M16A3 is very similar to the M16A2, but retains the original full-automatic firing mode of the M16A1 instead of the three-round burst mode of the M16A2. This variant was made for US Special Forces, who need the extra firepower afforded by the full-automatic firing mode. Special forces personnel are trained to maintain better fire discipline and not use up their ammunition so quickly. The US Navy was the first to order this variant, for use by its SEAL and Seabee units.

The M16A4 is the latest variant of the M16 family.

M16A4 rifles. Click on image to enlarge. Public domain image.

This is currently being issued to US Marine Corps front line units, and some US Army units. The main difference between this and the M16A2 is the removal of the fixed carrying handle/rear sight, which is seen on the M16A2. Instead, this is replaced by a Picatinny rail on the A4 model. This allows the user to not only attach a carrying handle, but also other accessories, such as a scope, as seen in the image above. The hand guards in front of the magazine are also of a new design (Knight Armament's M5 RAS handguard), which allows the user to attach a vertical grip, tactical light, laser sight etc.

The M16 rifle had initial teething issues, but has later evolved into a fine, reliable weapon, which is in use by several military forces around the world.

History and Development of the Assault Rifle - VI

2011-04-29T00:49:00.000-07:00

In our last post, we studied some of the history of the M16's predecessor, the AR-15. Where we left off was right at the end of development of the AR-15 by the Armalite Corporation. At this point, Armalite's parent company, Fairchild Aviation, decided that it had spent too much money on development expenses and wanted to get out of the firearms business. Hence, they sold the production rights to the Colt Firearms Company in December 1959, for $75,000 cash and 4.5% royalty on every unit manufactured. Shortly after this, Eugene Stoner left Armalite and began to work as a consultant for Colt.

Meanwhile, an USAF General, Curtis LeMay, witnessed a demonstration of the AR-15 in mid 1960 and became a proponent of the new weapon. Therefore, in 1961, he requested an order of 80,000 units for use by the Air Force. At that time, the US military was generally using the M14 rifle which fires a 7.62x51 mm. NATO cartridge. Hence, President John F. Kennedy, on the advice of US Army General Maxwell Taylor, stopped the AR-15 request on the grounds that having two different calibers within different military branches was a bad idea. However, another US government agency sent a batch of the new AR-15 rifles to South Vietnam, where it met with widespread praise by its users.

President Kennedy had appointed Mr. Robert McNamara as the Secretary of Defense at this point. Mr. McNamara was a former Ford Motor Company executive, who had risen up the ranks in Ford, becoming the first non-member of Henry Ford's family to become the president of the company. He had built his reputation by stopping Ford's losses in the late 40s and 50s by bringing in modern organization, management control and planning systems and was a big proponent of efficiency. Mr. McNamara started to push the various branches of the US military to adopt some common weapons, vehicles and aircraft to cut down costs (He was famously known as "Mac the Knife" in the Pentagon, for his cost-cutting measures). Now, after the enthusiastic reports about the AR-15 from South Vietnam, Mr. McNamara had to decide whether to believe the Pentagon's decision on sticking with the M14 or going with the positively glowing reports from South Vietnam about the new AR-15.

So he ordered Secretary of the Army, Cyrus Vance, to conduct tests between the M14, the AR-15 and the AK-47. The test results showed that the Army favored the existing M14, but then subsequent investigation showed that the testing methods were biased by the testers to favor the M14. In the end, Mr. McNamara ordered M14 production to stop in January 1963 because he determined that only the AR-15 could serve the needs of all branches of the US military. This was at a time when 5.56x45 mm. ammunition was not available widely, so the US Army tried to resist the change to the new rifle. The US Army also conducted a series of tests and wanted a few improvements done to the weapon:

Adding a chrome lining the inside of the barrel and the firing chamber in order to resist corrosion and wear and tear.
Adding a forward assist lever to push the rifle bolt into battery, in the event that a cartridge could not load into the chamber correctly due to corrosion or dirt.
Cleaning kits for the rifles.

Colt insisted that the design was self-cleaning and needed no maintenance and in order to cut costs, the first versions of the new rifle were released with no cleaning kits or chrome lining. Colt and the US Air Force also didn't want to add the forward assist lever, because it added an additional $4.50 to the cost of each rifle, but the US Army insisted upon this change. In the end, Colt decided to produce two versions, a US Airforce version called the M16, which has no forward-assist lever and another version, called the XM16E1, with the forward assist lever, for the other military branches. The XM16E1 was renamed as the M16A1 by the US Army. In November 1963, Mr. McNamara approved the US Army's order for 85,000 M16A1s for the US Army and an additional 19,000 M16 models for the US Air Force.

The M16A1 was sent to equip US troops in Vietnam, in 1965. Almost immediately, reports of jamming issues and malfunctions began to emerge. In several cases, dead US troops were found with jammed M16A1 rifles. A Congressional investigation was launched and the key culprit emerged -- it was the propellant used for the cartridges. The original cartridges used during the evaluation tests were manufactured by DuPont and used nitrocellulose based powder. However, these cartridges could not be profitably mass-produced and their propulsive force was just a bit below the desired specifications, when used in arctic conditions. Hence, a new cartridge from Olin Matheson was used instead, which used a mixture of nitrocellulose and nitroglycerin. This new propellant caused dirtier residue than the propellant used in the original cartridges when the rifle was first evaluated. Due to the fact that the rifle came with no chrome lining or cleaning kit, build up of residue could cause jamming issues. The new cartridge also burned faster and therefore increased the rifle's firing rate from 850 to 1000 rounds per minute, which caused extra stress on the rifle's springs.

Once the issues were identified, the US military quickly added chrome lining and also added a buffer system to reduce the firing rate to 650-850 rounds per minute. Cleaning kits and maintenance instructions were also issued and the rifle's failure rate immediately dropped. However, the early reliability issues gave this rifle a bad reputation in the beginning, and this bad reputation continued to dog the M16 for some years afterwards, even after the issues were all fixed. By 1968 though, the rifle began to gain popularity from US soldiers. A 1968 survey among 2100 US soldiers showed that only 38 individuals had wanted to replace the M16 with another weapon and of those 38 people, 35 of them had wanted the CAR-15, a carbine version of the M16!

Other NATO countries also wanted to share commonality with US military firearms and hence, they all began to adopt the 5.56x45 mm. cartridge.

In the next post, we will study the development and insight into the design of the various M16 variants that followed the M16A1 model.

History and Development of the Assault Rifle - V

2011-04-18T23:44:00.000-07:00

In the last few posts, we have been studying the developments of the AK rifle family designed in the Soviet Union. In the next few posts, we will study the development of the M16 assault rifle in the US.

We start our study around 1948, right after the end of World War II. An official US Army historian, Colonel (later Brigadier General) S.L.A ("Slam") Marshall was beginning to study the effects of combat on men and eventually authored several books on the subject. One of the most well known books was titled Men Against Fire, in which he claimed that during World War II, when US soldiers who were engaged in direct combat, 75% of them never fired their weapon directly at an enemy even when they were in combat. Per his research, there appeared to be a deep reluctance to kill another human being even at the risk of being killed. While some of SLA Marshall's research methods and conclusions were questioned much later on, in the 1950s and 1960s, he could do no wrong and was regarded as the ultimate authority. Other studies by the US army showed that people armed with automatic weapons were more likely to fire them in combat, because they were less likely to think about the consequences of killing another human. Still other analysis by the US army determined that most infantry combat occurred at relatively close ranges and that the side with the most firepower tended to win most engagements. The number of casualties of the enemy was found to be directly proportional to the number of bullets fired.

All these studies pointed to the fact that infantry soldiers should be provided with automatic weapons. However, this meant that the soldiers would use up ammunition more rapidly and would need to carry more of it into combat. This meant that the size and weight of the ammunition would have to be reduced in order to avoid overburdening the soldier. A research team in the US Army's Aberdeen Proving Ground facility in Maryland, was tasked with researching the effects of smaller calibers. They found that a .223 caliber (5.56 mm.) bullet moving at higher velocities had the same effects as larger rifle rounds in many combat situations and requested further funding from the US military to perform more experiments.

At the time that the US army was experimenting with smaller calibers, a division of Fairchild Aviation called ArmaLite was formed in 1954, to investigate uses of new materials and new designs for the firearms industry. It was a very small company at that time and the ninth employee was a talented weapon designer and Marine, who had served during World War II, Mr. Eugene Stoner. They produced an innovative rifle for the 7.62x51 mm. NATO cartridge that was in use at that time, called the AR-10. The AR-10 had several new features that were later featured in the M16. It used a direct impingement gas-operated action, unlike other piston and cylinder driven firearms (such as the AK family) used at that time. The direct impingement action didn't have a moving piston and hence was lighter and easier to keep pointed on target, especially when firing in fully automatic mode. Another feature, which was borrowed from the German FG-42 and Johnson LMG was the idea of a straight-line stock (i.e. the rifle stock is in line with the barrel), which serves to reduce muzzle climb. Previously, rifles would have a bend in the stock, so that the sights would be at eye level, while the recoil could be transferred to the shoulder of the user. With the stock inline with the barrel, a lot of the muzzle climb is significantly reduced (read the article on muzzle-climb linked above for why) and therefore, Armalite increased the height of the sights to compensate and the rear sight was mounted as part of the carrying handle. The receiver was hinged (a feature also found on the FN FAL), but unlike most other rifles, it was constructed of aluminum alloy, which made it lighter than other rifles of its class. The bolt locking mechanism was also innovative for its time. The AR-10 was much lighter, smaller and easier to control in automatic fire than any of its competitors. However, against the wishes of Eugene Stoner, the president of Armalite wanted the barrel to also be made of aluminum/steel composite, which made the rifle's barrel weaker. Hence, when they submitted it for army evaluation, it burst under a torture test and was rejected. Armalite quickly replaced the barrel with an all-steel model, but the damage was done and the US army rejected the rifle. However, the improved model was used by a number of other forces around the world.

Meanwhile, a US general named Willard Wyman received the funding request from the Aberdeen Proving Ground facility and he formed a team to develop .223 caliber (5.56 mm.) firearms for testing. The finalized requirement asked for a firearm capable of selective fire, to be under 6 pounds (2.7 kg.) when loaded with 20 rounds. The bullet had to penetrate a standard US steel helmet of that time period from 500 yards, while exceeding the wounding properties of a .30 carbine. General Wyman had also seen the AR-10 trials and was impressed by some of its innovative features, so he personally asked Armalite to design a weapon using the 5.56 mm. cartridge. The result was a scaled down AR-10 model called the AR-15:

AR-15 assault rifle. Click on image to enlarge. Public domain image.

The AR-15 entered the design competition and the weird thing was that it entered with very little competition, because the main competitor (Springfield Arms) did not feel like diverting resources because they wanted to concentrate on M14 production, which the US military was already using. The only other competitor was an entry from Winchester called the LMR.

During the testing, it was found that rainwater could accumulate in the AR-15's barrel (as well as in the Winchester's barrel), due to the smaller diameter and capillary action. When such a rifle was fired, it could cause the barrel and action to burst. See myth #3 for the reason why. History buffs may also like to read a declassified report of the issue. The rifle was not as accurate in arctic conditions either. However, its lightness and rate of fire meant that an 8 man team could have the same firepower as a 11 man team using the M14 rifle.

In the next post, we will look into the adoption of the AR-15 and how it morphed into the M16

History and Development of the Assault Rifle - IV

2011-04-17T03:24:00.000-07:00

In the last post, we studied the origins of the AK-47 and the beginning of the AKM. The AKM featured several improvements over the AK-47, mostly geared towards improving the production rate. In the initial AK-47 design, they had attempted to make the receiver out of stamped parts to speed up production, but the Soviets lacked the proper technology to do so and had issues with the resulting product. Hence, they resorted to machining the receiver from a block of metal, which was a slower process. However, in the 1950s, they used several captured German technicians to teach them metal stamping technology and hence the AKM featured a stamped receiver. Among the many improvements that the AKM had over the original AK-47:

Replacement of the milled receiver with a receiver made out of stamped sheet steel. Machining is a lot slower process than using a press to stamp parts. Hence, use of stamped parts made it much faster to produce AKMs.
Using rivets instead of welds on the receiver, in order to speed up production.
Improvements to barrel, gas ports etc. to speed up manufacturing and enhance reliability
Weight reduction of approximately 1 kg. (2.2. pounds)
Retains the chrome lined barrel and chamber of the AK-47 Type-2 variant, but the barrel is pressed and pinned to the receiver, instead of the AK-47 which has a threaded barrel that is screwed into the receiver.
The barrel is the first in the AK family to have a slant compensator to reduce rifle climb, when shooting in automatic mode.
Gas relief ports are moved forward to the gas block, instead of the gas tube.
Bolt carrier was lightened slightly. The wooden stocks were also hollowed out as well, in order to reduce more weight.
Sights on an AKM are calibrated to go up to 1000 meters, whereas AK-47s are only calibrated to go up to 800 meters.
Changes to the metal treatment applied. The AKM is parkerized instead of blued like the AK-47.
Uses modified spring and trigger assembly for better safety. The AKM fires in automatic mode only when the bolt is fully locked. The new trigger assembly also reduces "trigger bounce" and has a hammer release delay device to delay the release of the hammer by a few microseconds in automatic firing mode. The hammer release delay mechanism is sometimes incorrectly called a "rate reducer" by some people, but it doesn't appreciably change the cyclic rate of fire. Instead it allows the bolt group to settle in the forwardmost position after returning into the battery.

The Soviets made millions of AKMs and they weren't shy about handing out the plans to other co-operating countries, so that they could make their own as well. This is why AKMs are so widespread around the world.

AKM assault rifle. Click on image to enlarge. Public domain image.

The basic AKM design also has a number of variants. Some of these are:

AKMS - This is one of the commoner variants of the base AKM. The AKMS features a metal stock, which is foldable.
AKMP - This variation uses tritium front and rear sights for better visibility in low light conditions
AKML - This variant has a side mounting rail to mount a night vision device.
AKMLP - Same as AKML, but also has tritium sights as a backup.
AKMSP - Same as AKMS, but fitted with tritium sights
AKMSN and AKMSNP - Same as AKMS (i.e. foldable stock), but also has a side mounting rail to attach a night vision device. The AKMSNP version also has tritium sights.

History and Development of the Assault Rifle - III

2011-04-07T02:55:00.000-07:00

In this post, we will look at the history of one of the most famous assault rifles in history, the AK-47. The AK family is pretty widespread around the world these days, but there are widespread myths about its origins. The Soviet propaganda machine liked to portray that it was an original design entirely invented by a self-taught Russian peasant named Mikhail Kalashnikov. The real truth is actually somewhat different. We will study the history of this firearm in the following series of posts.

In the last post, we saw how the concept of the assault rifle was successfully used by the Germans. Their assault rifle was used against the Soviet Union with great success. The Soviets, in turn, analyzed some captured weapons and decided that it was a pretty good idea. Another major influence was the American M1 Garand rifle, which was also supplied to the Soviets in large quantities by the US and the Soviets decided that they must also have a reliable weapon that fires intermediate power cartridges. They quickly established a factory to manufacture 7.62x41 mm. ammunition, but needed a rifle to go with it. The initial requests for new rifle designs were sent to various Soviet bureaus in late 1943 and by the spring of 1944, at least ten designs were submitted by different groups. The Soviets adopted a design by one Mr. Sudayev and his design was called the AS-44. A limited run of the AS-44 was produced just after WW-II ended and the troops were generally happy with these weapons as they were better than what they had previously. However, the AS-44 was just too heavy and thus the Soviets opened another design competition in 1946.

Meanwhile, in a little known battle, called the Battle of Bryansk in 1942, a certain Russian T34 tank commander named Mikhail Kalashnikov was wounded in combat and made it to the hospital on foot, to receive medical treatment. During his recovery period, he vowed that he would make sure that his country would never be defeated again. While he was lying in bed, he overheard some other soldiers complaining about the quality of the Soviet rifles and his own experiences with the standard Soviet infantry rifles of that period also were similar. Hence, he began to design his own firearm, a sub-machine gun. While his sub-machine gun design was rejected because it was over-complex, his talents as a designer were noticed and he was reassigned to the Red Army's Small Arms Research division. Here, he designed a carbine, which was heavily influenced by the American M1 Garand rifle's piston driven gas-operated system (if the reader looks at an AK, it uses a gas-operated system almost identical to the Garand, except that the AK has the gas tube mounted on top of the barrel whereas it is below the barrel in an M1 Garand.) While this carbine also was not successful, it was the basis of a new assault rifle that was submitted to the Soviet design competition of 1946, the AK-1 (otherwise known as the AK-46). There were 16 other competing designs originally, with the old AS-44 acting as the benchmark standard and after the first round of trials, the AK-46 was chosen along with entries by A.A. Demetyev (the AD-46 rifle) and F. Bulkin (AB-46 rifle). In the second round of trials, the AK-46 was actually rejected because it did not perform as well as its other rivals, but Mikhail Kalashnikov managed to pull enough strings in the selection committee to continue work on his design and submit a new entry for the next round of trials. He went back to the drawing board with his assistant, Alexandr Zaitsyev, and decided to incorporate design features from other weapons (including some from his competitors, the AB-46 and AD-46!). The design of the AK-46's gas operated systems was already heavily influenced by the M1 Garand and the idea of the long stroke piston attached to the bolt carrier and return spring design were lifted from the AB-46 and the idea of large clearances came from the AS-44 and the safety lever mechanism was from the John Browning designed Remington 8 etc. The new design was dubbed the AK-47.

The other two designers were also given an opportunity to make design improvements for the next set of trials held in 1947. In the next round of trials, the F. Bulkin design (AB-47/TKB-415) was actually the most accurate of the three weapons and the AK-47 was last. However, the AB-47 had issues with parts wearing out quickly and the AK-47 beat out the other two handily in tests for durability and reliability. The selection committee made the decision that it is better to have a not-so-accurate-but-durable-and-reliable firearm than wait for an indefinite period for an accurate-and-reliable weapon and hence the AK-47 was chosen over its two competitors. The first version of this was deployed to limited troops between 1947 and 1948.

Initially the design called for a stamped steel receiver pinned at the front, for quicker manufacturing time. However, Soviet machine technology was not advanced enough to do this reliably and there were a large number of rejected receivers. Hence, the decision was made to manufacture the receivers using various machining operations. This made the manufacturing processes slower, but at least they could make reliable receivers this way. Therefore the AK-47 Mark I featured a machined receiver.

Meanwhile, a designer named German A. Korobov began to make an improved assault rifle design himself. Korobov had actually submitted a bullpup assault rifle design (the TKB-408) for the original design competion of 1946, but it was rejected after the first round of testing. Nevertheless, he continued to experiment with other bullpup and traditional rifle designs. By 1952, he switched to using the lever-delayed blowback action invented by Hungarian designer, Paul Kiraly. This led to more accuracy and simpler production for his design. In 1955, the Soviets started another design competition and the improved Korobov design (TKB-517) was submitted to the competition.

Meanwhile, the AK guys were not sitting idle either. They recruited several captured German engineers, including the renowned Hugo Schmeisser (the designer of the StG44) and learned mass production techniques from them. Their new design submission for the 1955 competition was the AKM (AK Modernizirovanniy, the Russian word for "Modernized").

Believe it or not, the TKB-517 pretty much beat the AKM on almost all counts. It was more accurate (especially in full automatic mode), significantly lighter and about 1/3rd cheaper to manufacture. So why did the Soviets adopt the AKM then? Because the selection committee decided that since the troops were already familiar with the AK-47, it would not be a good idea to replace it with a firearm that uses an entirely new design. Hence, the less-reliable, but more familiar AKM beat out the more accurate, but new design, TKB-517.

In the next post, we will look at further developments of the AK-47.

History and Development of the Assault Rifle - II

2011-03-21T00:42:00.000-07:00

When World War I started, the French introduced a light machine gun called the Chauchat. While it was capable of selecting both single and automatic firing modes, this firearm used full sized cartridges, unlike an assault rifle. It was also a notoriously unreliable weapon, because it did not function well under muddy conditions and jammed frequently because the slots cut into the magazine would let in dirt and mud. The .30-06 version also frequently jammed after a few shots once the gun became hot. In fact, it has the dubious distinction of being dubbed "worst machine gun ever" by several firearms experts. Still, it was not only used by the French, but also other allies such as Belgium and the United States. Captured Chauchats were even used by the Germans because they didn't have any comparable automatic firearms.

Chauchat Machine Gun. Click on image to enlarge.

Due to the Chauchat's unreliability under battlefield conditions, US troops turned to the redoubtable John Browning for help and he delivered the M1918 Browning Automatic Rifle (BAR) design in 1918. This weapon was introduced rather late in the war, but was very effective when it was used during this short time. The first time it was used was September 13th 1918 and one of the people demonstrating its use against the enemy was John Browning's son, Val Allen Browning.

Browning Automatic Rifle. Click on image to enlarge. Public domain image.

The BAR was so successful that the French ordered 15,000 of them to replace their own Chauchats! The BAR remained in production until the 1950s.

Note that both the Chauchat and BAR use full-size rifle cartridges. There were also automatic weapons designed during World War I, that used pistol ammunition. The most famous of these was the Thompson submachine gun, the so called "Tommy gun" that we studied about previously, when we studied the Blish lock mechanism. Both the Tommy gun and the BAR were designed rather late in the war though and the Tommy gun never saw action in World War I, but saw plenty of action in the hands of mobsters.

During the peace time period of World War I, several people argued for a new intermediate cartridge that was smaller than existing rifle cartridges, but bigger than pistol cartridges, and a suitable weapon to fire this new cartridge. The Swiss designer Furrer made an intermediate 7.65x35 cartridge for a carbine in 1921 and one Hauptmann Piderit of the German Rifle Testing Commission also advocated a shorter cartridge and a rilfe to fire it. Colonel Fedorov, who we studied in the previous post, was also arguing for a smaller cartridge. There were also experimentes made in Denmark and the US.

It was however, Germany, where some of the major new development took place. The Germans had observed that a small group of soldiers could easily overcome a larger group, provided that they had superior firepower. It was also observed that most infantry combat happened at less than 400 meters or so. By the 1930s, at least 5 German companies (Geco, DWM, RWS, Rheinmetall and Polte Patronenfabrik) were experimenting with intermediate rifle cartridges. It was Polte that was officially awarded the contract to design a new intermediate cartridge by the German military and after some experiments, came out with the 7.92x33 mm. "kurz" (German for "short") cartridge in 1938.

Contracts to design a new rifle for this cartridge were sent to both Walther and Haenel GmbH. Haenel's chief designer was Hugo Schmeisser and his design won out over the Walther design and was designated as the Maschinenkarabiner 1942 (after 1942, the year it was adopted) or MKb 42 for short. It underwent some minor design modifications, as requested by the German military. The Haenel design originally used an open bolt mechanism, but after a few trials, it was requested to make a closed bolt design similar to the Walther entry.

As it turned out, Adolf Hitler was strongly opposed to the new intermediate cartridge and demanded that more submachine guns be built instead. However, the German armament office secretly kept working on this new firearm and to avoid raising suspicions, they christened the weapon as MP 43 (MP = Machine Pistol). Hitler later asked for it to be renamed the MP 44, after some official tests in April 1944, unaware that it was not a machine pistol at all. In July 1944, Hitler held a conference with his generals on the Eastern Front and asked them what they needed most. A general who had no idea that the German armament office had disobeyed Hitler's orders, replied, "We want more of those new rifles!" and a thoroughly confused Hitler asked, "What new rifles?" and the cat was out of the bag. Some people thought they would be executed for disobeying Hitler's direct orders, but once Hitler was given a chance to test-fire the new MP 44 for himself, he became very impressed and enthusiastically gave it the name Sturmgewehr, which is German for "Storm (Assault) Rifle" ("Storm" as in storming a castle or assaulting a castle). This is where the term "Assault Rifle" comes from. Because of this new official name, the MP 44 was rechristened the StG 44.

Sturmgewehr 44 (StG 44), the first firearm to be called "Assault Rifle". Click on image to enlarge. Public domain image.

The StG 44 was heavily used in the Eastern Front and found extremely useful by soldiers. It was also very reliable in the extreme cold conditions of the Russian winter. It had a longer range than the Russian submachine guns, but a comparable rate of fire, switchable firing mode from single shot to full automatic mode, pretty decent accuracy and decent controllability even in fully automatic mode.

The StG 44 is now generally accepted as the world's first successful mass produced assault rifle. It was an encounter with one of these that prompted a Russian tank mechanic to invent his own assault rifle, which would later become one of the most famous designs world wide. But that is the subject of another article.

History and Development of the Assault Rifle - I

2011-03-19T01:32:00.000-07:00

In the next series of posts, we will study the evolution of the modern assault rifle.

First let us go back a few centuries in time and study how infantry warfare worked in the 1600s, 1700s and part of the 1800s. Back in those days, most firearms were smoothbore muskets, such as the famous Browm Bess, which was in service with the British military for over 100 years. Since muskets had no rifling, accuracy was somewhat limited. Also, since these firearms were muzzle loaders using mostly flintlock firing mechanisms, they were slow to load and use. Therefore the standard military strategy of the day was to line up three lines of troops about 50-100 meters away from the enemy. The first line would fire their weapons and immediately retreat to the rear. The second line would then step forward and in turn discharge the weapons and then retreat to the rear and the third line would repeat the same process. Meanwhile, this would hopefully give the first line enough time to reload their firearms so they could fire another volley. Each line was coordinated by an officer so that all the men in one line would fire at approximately the same time. This strategy also maximized the firepower of the unit. Since the firearms weren't very accurate, it was hoped that the massed fire would hit at least some of the enemy troops. In fact, Colonel George Hanger of the British Army famously said, "A soldier's musket, if not exceedingly ill-bored (as many are), will strike a figure of a man at 80 yards; it may even at a hundred; but a soldier must be very unfortunate indeed who shall be wounded by a common musket at 150 yards, providing his antagonist aims at him; and as to firing at a man at 200 yards with a common musket, you may as well fire at the moon and have the same hope of hitting him. I do maintain and will prove…that no man was ever killed at 200 yards, by a common musket, by the person who aimed at him."

In the 1800s, with the advent of rifled firearms, massed fire tactics and tight formations began to fade away. As accuracy was improved, it was no longer practical for soldiers to fire at each other from standing positions over a plain. It took a while for military planners to realize that massed fire tactics were obsolete though, as can be witnessed by the huge casualties in the American Civil War, where men still shot at each other in tight formations at distances less than 100 yards apart. The final death knell of the massed formation strategy came in World War I, where the machine gun, trenches and artillery rendered this method obsolete. Instead, troops took pot shots at each other from longer ranges and from trenches.

In 1890, an Italian officer named Amerigo Cei-Rigotti invented an rifle, which was capable of selective fire (single shots or burst mode). The rifle was designed to fire 6.5x52 mm. ammunition from a detachable magazine. Incremental modifications were made to the rifle until 1900 before it was dropped from consideration. While this was the first real "assault" rifle, it wasn't very popular because it was extremely unreliable and had a very high rate of misfiring and jamming. That is why it was never adopted by any military anywhere.

The next development was the Fedorov Avtomat from Russia, in 1916. This particular firearm was developed by Vladimir Fedorov. This firearm was relatively lighter weight than other firearms of its time, had a large detachable magazine, had capability to switch firing mode from single shot to automatic mode and used an intermediate powered cartridge (smaller than a rifle cartridge, but larger than a pistol cartridge). The cartridge used for this was originally a custom designed 6.5 mm. cartridge, but it was later switched to use a 6.5x50 mm. Japanese designed Arisaka cartridge because it was available in quantity already. While this cartridge appears big compared to modern cartridges, remember that ammunition was not as powerful in those days, so it could be considered as an intermediate power cartridge. The Fedorov Avtomat was not produced in great numbers, but it was popular with Russian troops until World War II.

Federov avtomat assault rifle. Click on image to enlarge. Image is in the public domain.

The Fedorov Avtomat was influential because it was the first practical assault rifle that was adopted by a military anywhere. Incidentally, its inventor, Colonel Fedorov, also invented the concept of the infantry weapon family, where carbine, assault rifle, light machine gun, medium machine gun etc. would all share some commonality of parts (e.g.) action, receiver, trigger assembly etc.

Utility Firearms: Line Throwing Gun

2011-03-13T14:53:00.000-07:00

In maritime history, there have been several cases where a ship has foundered close to shore and no one could be rescued because a rescue rope could not be sent to the ship. Therefore, in the 1800s, work began in the development of tethered projectiles that could be used to pass a rope to a ship.

The same need is also encountered in civil engineering projects when one needs to pass a rope over a chasm.

Even though development had started in the early 1800s, the first practical development to solve this problem didn't happen until 1850, when Captain David A. Lyle, a West Point and MIT graduate, sat down to solve the problem. He designed a short barreled cannon using a custom designed shot and special waterproof braided linen line. The cannon was named the Lyle gun in his honor.

A Lyle gun in use. Click on image to enlarge. Public domain image.

The Lyle gun had a range of about 700 yards. It also had huge recoil and hence, it was mounted on a small cart. The Lyle gun stayed in use until 1952 and similar models were also made by several other companies.

While the Lyle gun was technically a cannon, there were other hand-held line throwing guns being made as well.

Click on image to enlarge. Public domain image.

The above image shows a gun made by the English gunmaker, W.W. Greener, capable of throwing a line about 150 yards or so.

William Schermuly, a British inventor of Dutch origin, came up with the idea of using rocket propulsion to toss the line, instead of using gunpowder. While his early experiments of 1897 just consisted of a rocket in a tube with a line attached to it, he began to work on a better device that could be small, light, accurate, have a long shelf life, safe and simple enough for a child to operate. In 1927, he came up with the concept of a rocket fired from a hand-held pistol, the SRPA (Schermuly Rocket Pistol Apparatus):

Click on image to enlarge.

This device had very little recoil, was not affected by cross-winds, weatherproof and the path of the rocket was visible so that people could easily correct their aim if needed. On top of that, it was light and simple enough that Schermuly got his 8-year old grandson to demonstrate its use to members of the British parliament.

By the time William Schermuly died in 1929, it became compulsory for any vessels over 500 tons to carry line throwers. The company was carried on by his sons and produced many other rocket based products, such as grappling hooks, rescue apparatus and flares during World War II.

Line throwing guns are still in use and they're still being made by some companies, such as Naval Gun Company Inc., which makes the official CG85 Bridger Line Throwing Gun Kit for the US Coast Guard.

H&R Bridger Line throwing gun made by the Naval Gun Company Inc. Click on image to enlarge.

A US Navy sailor aboard the aircraft carrier USS Dwight D. Eiserhower prepares to shoot a line to USNS Tippecanoe.

The line will be used to set up a bigger line and perform refueling and replenishment at sea.

Such apparatus are used by coast guard, navy, firefighters, construction companies, offshore drilling rigs, commercial fishing fleets, tugs, barges etc.

Utility Firearms: Drill Rifle

2011-03-13T00:20:00.000-08:00

Many of us have watched military units performing rifle drills in parades. The USMC's Silent Drill platoon is one of the more well known units here in the US. How many of you know that the rifles they use are inert? That is the subject of today's post: the Drill Rifle.

A drill rifle is based on a normal rifle, but it has one key difference: it cannot actually be fired. So why make a firearm that cannot be fired? It can be used to train cadets on the use of a rifle, before they go out and fire the real thing. It can also be used safely for drill demonstrations. It cannot be used by a disgruntled cadet to take shots at a crowd or a chief guest (yes, this has happened in the past in some countries). In the UK, the Lee Enfield L59A1 Drill Rifle was specifically developed because there was some concern about the Army Cadet Corps and Combined Cadet Corps having their equipment stolen by the IRA.

Modifications from a standard rifle include clipping the firing pin short so that it can't impact a round in the chamber, welding the barrel shut, welding the striker hole in the bolt shut, welding the barrel to the receiver so that it can't be removed and fitted with another barrel, removing locking lugs, cutting part of the barrel internally, removing sights etc.

The end result: a rifle that looks very close to the real thing, but is incapable of firing and needs a large number of modifications before it will ever come close to firing anything. The USMC Silent Drill platoon uses inert versions of the M1 Garand rifle and US Navy uses inert versions of the M1903A3 Springfield rifle for their drill purposes.

Utility Firearms: Meat Processing Industry

2011-03-11T22:28:00.000-08:00

In the meat processing industry, there are certain tools that are used to enable a quick humane death of a food animal. There are two basic types of firearms used here: (a) captive bolt type and (b) free bullet type. We will study both types in this post.

The first captive bolt pistol was invented by one Dr. Hugo Heiss of Straubing, Bavaria, Germany in 1903. The captive bolt type of firearm serves to stun an animal into unconsciousness, so it may then be processed. The pistol is placed against the skull of the animal and the trigger is pulled. The captive bolt pistol, as its name indicates, does NOT actually fire a bullet. Instead, it uses the force of compressed air, or a blank cartridge, to push a bolt forward with great force, which drives it into the animal's skull, thereby stunning it. After the blow is struck, spring tension pushes the bolt back into the device, as the figure below illustrates:

There are two types of captive bolt pistol: (a) the penetrating type, where the bolt has a sharpened tip and actually penetrates the skull into the brain of the animal and (b) non-penetrating type, where the bolt has a blunt rounded tip and doesn't penetrate the skull, but uses the concussive force generated to stun the animal. The pictures below show examples of both types:

Captive bolt pistol with penetrating bolt. Click on image to enlarge

Captive bolt pistol with non-penetrating bolt. Click on image to enlarge

Captive bolt penetrating type pistols driven by compressed air are now banned in the United States after a case of BSE (Bovine Spongiform Encephalopathy) was detected in 2004. This is because the compressed air (unlike using a blank cartridge) forces infected brain matter into the bloodstream of the slaughtered animal. Since cattle blood is reprocessed for protein supplements in animal feed and milk replacements for calves, it could potentially spread the disease to other animals. Penetrating type pistols using blank cartridges and non-penetrating types are considered safe.

Since the bolt (i.e. the projectile) does not entirely leave the pistol, captive bolt pistols are not regarded as "firearms" in many jurisdictions and hence do not need any special paperwork.

The other type of firearm used in the meat processing industry is the free bullet type. In this case, a real bullet is indeed fired out. They are essentially small-caliber pistols designed specifically for putting an animal down. One of the first practical ones was designed by the famous English firm W.W. Greener of Birmingham in 1865. Called the Greener Humane Cattle Killer, this device quickly became the standard of the British War Office in the Veterinary and Butchering departments, was adopted by the British Admiralty's Victualling yards and was adopted by many veterinarians and butchers.

It consists of a short rifled barrel with a bell shaped muzzle. The bell serves to muffle the sound of explosion as well as protect the operator from muzzle flash. It has an ordinary spring striker that is struck by a wooden mallet. The piece containing the striker is screwed off the barrel, a cartridge is then inserted into the chamber and the piece screwed back on. The instrument is placed on the animal's forehead and the back end is tapped with a mallet to discharge the weapon. This model uses specially designed low power .310 caliber "cattle killer" cartridges manufactured by Kynoch Ltd.

Even though they weren't considered "firearms", such devices had to undergo proof tests and since W.W. Greener's main factory was located in Birmingham then (the firm's headquarters are now in Chippenham), these devices were marked with Birmingham Proof House markings.

Despite the small caliber bullet, if placed in the correct spot, only a single shot is needed to put an animal down. Since this spot varies for different animals, Greener included a set of diagrams in the package, indicating the best spot to use for different farm animals.

W.W. Greener produced several versions of this, including a pocket version for veterinarians, which was very popular. The model finally became obsolete in the 1960s when its unique .310 caliber cartridges became almost impossible to obtain. Due to demand, the firm has recently started manufacturing a Mark II version that uses a .32 ACP cartridge. W.W. Greener also made other models manufactured in different calibers to put down horses, sheep, pigs etc. and even a special version designed for use on dogs alone.

Utility Firearms: Industrial Shotguns

2011-03-06T23:57:00.000-08:00

In our last post, we saw the use of shotguns in geological engineering. In this post, we will look at some more unusual uses of shotguns, in the fields of industry.

In industries like steel and cement, when a lime kiln or a blast furnace is used, there is always a gradual build up of material impurities, such as limestone clinker and excess cement (in the case of a lime kiln) or slag deposits (in the case of a blast furnace). These impurities harden on the inside and form rings, which reduce the efficiency of the kiln or blast furnace. Hence, a worker must periodically go in there and loosen the materials so that they can be removed. The same problem occurs in silos, mines and quarries for pretty much the same reasons.

In the early days, people would shutdown the kiln or furnace and wait for it to cool down. Then they would get inside with large sledgehammers and try to break the deposits manually. Then someone had the bright idea of using a large gauge shotgun to blaze away at the deposits and break them. This meant that they wouldn't have to wait for the kiln to cool down. The image below is a description of the process as it appeared in an issue of Popular Science in February 1933.

Click on image to enlarge.

The guns used in this process are usually 8-gauge or larger. They are mounted on a stand so that the user doesn't have to bear the recoil forces. Winchester and Remington are two major manufacturers of kiln guns. Remington's system is called "Masterblaster" and is usually painted green, while Winchester calls their tools "Western" and "Ringblaster" and usually paint them red.

Remington Masterblaster system. Click on image to enlarge.

Note the control wheels and levers that allow the user to point the shotgun in the designated direction and shoot it.

A kiln gun in use. Click on image to enlarge

Using such a system allows the manufacturer to speed up the cleaning process and reduce equipment downtime.

Since the shooting happens largely parallel to the kiln surface, there is less risk of blowing holes through the kiln. The video below shows the usage of kiln guns (in this case, Winchester products):

They can also be used for furnace tapping as the video below demonstrates:

As you can see, kiln guns are pretty handy tools to have in industrial environments.

Utility Firearms: Geology and Shotguns

2011-03-06T14:44:00.000-08:00

Continuing our series on utility firearms (i.e.) firearms not designed to take human life. We will discuss the use of shotguns in the field of geology and geological engineering in this post.

There is a physical principle called "seismic refraction". Basically, when seismic waves travel through the ground, the waves move at different velocities depending upon the various different layers of soil or rock. Also, the waves get refracted (i.e. they change their angle of travel) when they cross between two different layers of soil or rock. So if one has a source of seismic energy on one side and a detection device (a seismograph or a geophone) a short distance away, one can detect the seismic waves and determine the approximate depth of various layers or the depth to the bedrock, for instance. This is very useful in civil engineering and geological engineering, because engineers need to know if the soil can actually support the structure they're planning to build. Exploration geophysicists also use this technique to detect positions of mineral ores, oil, groundwater, geothermal sources etc.

So where does the shotgun come into all of this? Note in the previous paragraph, we said that there needs to be a source of seismic energy and a detection device. The source of seismic energy is simply something that impacts the earth surface with sufficient force to create seismic waves. For instance, one can use a sledgehammer to strike a metal plate on the ground. The sledgehammer is connected to the geophone recording system via a wire. The moment the sledgehammer impacts the metal plate, the recording starts. Of course, there are problems in using a sledgehammer in that (a) the results are not reliably repeatable as it depends on how tired the person swinging the sledgehammer is (b) it only outputs small amounts of seismic energy and only works on short distances and (c) it generates low frequency waves that mostly travel along the surface and don't penetrate too deep.

Therefore, what many people use is a shotgun (around 8 gauge or larger) to produce the seismic energy. The shotgun is usually mounted on a stand or a cart, so that even a weak person can operate it, without having to feel any recoil. In some cases, the shotgun actually fires a solid slug into the ground and in other cases, they merely use a blank shotgun shell, in which case the pressure energy of the column of air in the barrel is transferred to the ground. Like the sledgehammer method, there is a mechanism to start the geophone recording the instant the slug hits the metal plate placed on the ground. The advantages of this over the sledgehammer method are:

Easily transportable and usable by even physically weak people (since it is on a stand and doesn't need to be fired from the shoulder)
Highly repeatable source of seismic energy (much more than using a sledgehammer)
Outputs higher frequency waves, so they penetrate the ground more.

Such shotguns are often called "Betsy Guns". Here's a couple of examples of what they like:

Public domain image. Click on image to enlarge.

Image courtesy of Thomas M. Boyd @ Colorado school of Mines

Of course, this equipment is a bit more bulky and expensive than a simple sledgehammer and there's also the question of getting permission to use a shotgun in certain countries, but it is still a commonly used method in many places.

For deeper penetration of seismic waves, users generally use something more powerful, such as dynamite. But that's not a firearm and we won't discuss it here :).

Utility Firearms: Powder Actuated Tools

2011-03-06T02:04:00.000-08:00

In our previous post, we started a series of posts on firearms being used for purposes other than to take human life. Our previous post dealt with the topic of flare guns (Very pistols). In this post, we will look into uses of firearms in construction (i.e.) a Direct Fastening Tool or Power Actuated Tool.

A powder actuated tool is actually a form of a nail gun, that is used to nail one object to another. Powder actuated tools are used in situations where one needs to nail something on to a hard substrate, such as steel or concrete. The technology relies on exploding a propellant (usually cordite) and using the resulting gas pressure to drive a nail (or, more correctly, a "fastener") instead of a bullet through the surfaces of the objects to be fastened together. The technology was first invented around World War I and used for submarine hunting and there is a US patent from 1921 (US patent # 1365869) describing one. During World War II, the Mine Safety Appliance Corporation (MSA Corp.) designed and built several powder actuated tools for the US Navy, that could be used to temporarily repair steel ship hulls in an emergency.

There are two types of powder actuated tools: high velocity type and low velocity type. In the high velocity type, the propellant directly acts on the fastener. In the low velocity type, the propellant acts on a piston, the other end of which acts on the fastener. A tool is considered low velocity type, if the fastener is driven slower than 492 feet per second. High velocity type tools are illegal to be made or sold in the United States, but there are some made decades ago, still in use by shipbuilding and steel industries, that were grandfathered in because they were made before the law took effect.

Since the fasteners are designed to go through very hard substances, they are usually made from high quality hardened steel. Fasteners need not be just nails, they could be specialized fasteners, such as ones that have a screw thread in the end, to attach a nut.

Powder actuated tools come in several types (e.g.) single shot or magazine type, manually fed (i.e. you load fasteners and cartridges manually) semi-automatic type (i.e. cartridges are automatically loaded from the magazine, but fasteners are manually loaded) or fully automatic type (i.e. both fasteners and cartridges are automatically loaded) etc.

Public domain image of some cartridges used by powder actuated tools.

The main manufacturers of these tools are five companies: Simpsons Strong Tie, Ramset Fastening Systems, Powers Fasteners and Remington from the US and Hilti of Luxembourg. The above images show a Hilti DX E72 and a Simpson PT-25S tool and two strips of cartridges to be used by such tools. The cartridges may be unloaded from the plastic strip and manually loaded one by one for manual type tools, or the entire strip may be loaded directly into the magazine for semi-automatic and automatic type tools. Cartridges are usually sold in boxes of different colors to indicate their relative power. The plastic strip that the cartridges come in is also the same color to indicate the power. The colors used are (in order from weakest to strongest) gray, brown, green, yellow, red and purple. The video below illustrates the use of a powder actuated tool, different fasteners and different cartridge types

In some countries, powder actuated tools are very strictly controlled, e.g. the owner has to register the tool as a firearm and the operator of the tool requires specialized training and has to possess a license to use it. In the US, no new high velocity type tools are allowed to be made or sold, but older high velocity type tools that were made before the laws came in effect are grandfathered in. Low velocity type tools may still be made and sold in the US. US labor law also requires that operators receive special OSHA training before they are allowed to use such tools.

Utility Firearms: Flare Gun or Very Pistol

2011-03-06T01:05:00.000-08:00

In this next series of posts, we will look at some utility firearms that were usually not used to take human life. The first one we will look at is the Flare Gun, otherwise known as the Very Pistol.

The name "Very Pistol" is derived from the name of the inventor, Lieutenant Edward W. Very, of the United States Navy. He invented a large caliber single-shot pistol with a single action firing mechanism, that could fire special flares into the air. It was designed to be used by people to send signals and reveal their position, usually to indicate that they were in distress and needed assistance. Flare guns were heavily used in both world wars and are still in use today. The flare guns of World War II era had a 1-inch bore (25.4 mm) and modern ones are smaller (12 gauge (18.53 mm.) diameter) Modern versions are usually made of brightly colored plastic, so that they're easy to find in an emergency situation.

World War I era 1-inch caliber Webley & Scott Mark III flare pistol, British Army, dated 1918. Click on image to enlarge

Image licensed by user Andy Dingley @ wikipedia.org under the Creative Commons Attribution-Share Alike 3.0 Unported License.

Modern 12 gauge flare gun manufactured by Orion Electronics. Note the bright plastics on this model. Click on image to enlarge.

The flares come in three colors, red, green and "white star", and have a burn time of anywhere between 5 to 10 seconds, depending on flare type. Distress flares are typically shot straight up in the air, for maximum visibility time of the flare and also to show where the person in trouble is. During World War I and II, flare guns were also used in situations where radio silence was important. By firing sequences of pre-arranged colored flares, aircraft and ground forces could identify each other's positions and send specific signals.

Flare guns aren't made as strongly as normal firearms, so it is extremely unwise to try shooting a normal 12-gauge shotgun cartridge out of a flare gun, as the flare gun is likely to explode in the user's hands.

While flare guns are not designed to be a weapon, there have been instances where they've been used in that role. In World War II, a German pilot, Oberleutnant Arnim Faber, accidentally landed in an airfield in Wales and was captured by the duty pilot, Sgt. Jeffries, who didn't have a normal firearm and hence grabbed the nearest thing available, which was a Very pistol. When the USS Borie was hunting for the German submarine, U-405, they rammed into each other and hand-to-hand fighting ensued, where at least one of the crew of the U-405 was hit in the chest by a Very flare fired by the crew of the USS Borie.

The most famous use of a flare gun is immortalized in the song, Smoke on the Water, by the British hard rock band, Deep Purple. Many people, even those that never listen to hard-rock or heavy metal music, will instantly recognize the opening guitar riff of this song, even if they don't know the title of the song. The story behind the song is this: the members of Deep Purple were in Montreux, Switzerland, trying to record a new album at an entertainment complex that was part of the Montreux casino. Meanwhile, Frank Zappa and the Mothers of Invention were playing a concert inside the casino theater, as part of the Montreux jazz festival. During the concert, a member of the audience fired a flare gun inside the venue. The ceiling caught fire, but the audience initially thought it was part of the show. The resulting fire ended up burning the entire casino down. The members of Deep Purple were watching the blaze from across the lake and were inspired into writing a classic song that has since been covered by countless hard-rock and heavy metal bands. The lyrics of the song make references to the flare gun.

Shotguns: Different Gauges

2011-03-01T00:14:00.000-08:00

Well, we did study shotgun bores/gauges in an earlier post. But it is hard to visualize the effects of the different gauges from just a description.

No fear, the lovely and talented Heather LaCroix is here, demonstrating the effects of 10 gauge vs. 12 gauge vs. 20 gauge vs. .410 caliber (67 gauge). Remember from our earlier discussion of how shotgun gauges work, the smaller the number, the bigger the diameter of the cartridge and the more powerful the gun.

Thanks to Heather LaCroix and Jeff3230 for the demonstration.

Shotguns: Coach Gun

2011-03-01T00:01:00.000-08:00

In our first article on shotgun basics, we studied the origin of the term "riding shotgun". This had to do with a particular type of shotgun, which was called the coach gun. A typical coach gun was a double barreled shotgun with barrels between 12-18 inches in length or so. Barrels were invariably placed side-by-side and typically were mostly 12-bore. The sights were typically a bead sight welded on to the barrels, as aim wasn't as critical at close ranges. They were generally loaded with buck shot and very effective at close ranges. Virtually all coach guns had twin triggers and most had external hammers, though there are a few hammerless models made.

The term "coach gun" came into use because of Wells Fargo bank. In 1858, they opened a stage coach route between Tipton, Missouri and the fast growing city of San Francisco, California. Not only did they transport passengers on this route, they also transported mail for the US post office, as well as large sums of paper money and gold to their branches. The route was 2800 miles long and passed through some of the wildest parts of the United States. Naturally, this attracted the attention of bandits and highwaymen and so these stage coaches were pretty heavily guarded. The driver of the stage-coach was at a disadvantage, because he had to concentrate on driving the horses, hence they would put a person next to him with a coach gun, to defend the two of them as needed, and there were additional guards inside the stage coach as well. Since it is difficult to hit a moving target from a bouncing stage coach, which is also moving at speed, the guards preferred a coach gun to a rifle, since all one needed to do was point the gun in the general direction and pull the trigger.

The same idea was also later used in Australia, by banks seeking to transfer large sums of money across different Australian towns.

There was no specific coach gun maker, as many manufacturers were making them: Remington, Lefever, Ithaca, Sharps Arms Manufacturing, Colt, Parker etc. are some of the famous names that made them.

As you can see from the above video, they can pack a punch.

Coach guns are still being manufactured by some companies, but sale may be restricted in certain areas, due to rules about what the minimum length of a shotgun should be.

What are the differences between AK-47, AKM, AK-56, AK-74 and AK-101?

2011-02-26T02:16:00.000-08:00

The AK family of assault rifles are pretty widespread around the world, because of their lower cost of manufacturing, lower tooling costs, general reliability under rough conditions and the fact that the former Soviet Union were pretty much handing them out like candy for years. Clones of the original AK design have also been manufactured by other countries: China, Bulgaria, Romania, even companies in the good ol' USA. Unfortunately, the media keeps referring to just about any assault rifle in the AK family as the "AK-47". This post aims to point out some members of the AK family and some of their major differences.

The AK is a Russian abbreviation for Avtomat Kalashnikova. The name Kalashnikova comes from the fact that its inventor is Mikhail Kalashnikov. The original development for this rifle started in 1945 and a prototype (the AK-46) was submitted for evaluation in 1946, but it was only in 1947 that it was cleared for production for use by select Soviet forces. There have been several improvements to the original design over the years and there are now many models in the AK family. With that little bit of history said, let's now study some of the key features of some models.

AK-47: This is the original version that was approved for use by the Soviets. It fires a 7.62x39 mm. cartridge. It was originally approved for some Soviet forces in 1947, which is why the name has 47 after it. During 1948-1951, it went into general production to be used by other Soviet military units as well (the Type-1 model). In 1952, the Type-2 version was introduced, which had a chrome plated barrel and receiver to resist corrosion and wear. The Soviets had originally tried to make the receiver out of stamped sheet metal, but didn't have the technology then to produce the part reliably. After a large number of rejections of faulty receivers, the Soviets opted to use a receiver made of forged steel, which was milled into the final shape using various machining operations. This made the overall production rate slower.

AK-47 Type 2 variant. Click on image to enlarge. Public domain image.

AKM: This is a popular variant of the AK family. This was created as an improvement of the original AK-47 design. The letter M in the name "AKM" stands for Modernizirovanniy, which is the Russian word for "modernized." The AKM design was developed in the 1950s and finally was approved for full production in 1959. It fires the same 7.62x39 mm as the AK-47 for backward compatibility. However, the design was much revised and enhanced from the original AK-47 to allow it to be mass-produced. The Soviets acquired modern mass production technologies from captured German engineers (including Hugo Schmeisser, the designer of the StG-44) and used those on the AKM. Among some of its improvements:

Replacement of the milled receiver with a receiver made out of stamped sheet steel. Machining is a lot slower process than using a press to stamp parts. Hence, use of stamped parts made it much faster to produce AKMs.
Using rivets instead of welds on the receiver, in order to speed up production.
Improvements to barrel, gas ports etc. to speed up manufacturing and enhance reliability
Weight reduction of approximately 1 kg. (2.2. pounds)
Retains the chrome lined barrel and chamber of the AK-47 Type-2 variant, but the barrel is pressed and pinned to the receiver, instead of the AK-47 which has a threaded barrel that is screwed into the receiver.
The barrel is the first in the AK family to have a slant compensator to reduce rifle climb, when shooting in automatic mode.
Gas relief ports are moved forward to the gas block, instead of the gas tube.
Bolt carrier was lightened slightly. The wooden stocks were also hollowed out as well, in order to reduce more weight.
Sights on an AKM are calibrated to go up to 1000 meters, whereas AK-47s are only calibrated to go up to 800 meters.
Changes to the metal treatment applied. The AKM is parkerized instead of blued like the AK-47.
Uses modified spring and trigger assembly for better safety. The AKM fires in automatic mode only when the bolt is fully locked. The new trigger assembly also reduces "trigger bounce" and has a hammer release delay device to delay the release of the hammer by a few microseconds in automatic firing mode. The hammer release delay mechanism is sometimes incorrectly called a "rate reducer" by some people, but it doesn't appreciably change the cyclic rate of fire. Instead it allows the bolt group to settle in the forwardmost position after returning into the battery.

AKM assault rifle. Click on image to enlarge. Public domain image.

Note the slanted barrel tip: that is the muzzle brake, which is one of the improvements over the original AK-47 design

The AKM was used by the Soviets, most Warsaw Pact countries, several African countries and many Asian countries as well. Manufacturing licenses, as well as necessary technical data, were sold for very nominal rates (or gifted for free!) to Warsaw Pact countries, as well as other "friendly" countries like Egypt and Iraq, so that they could make their own AKMs. Because of this, it became very widespread around the world. Many variants of this design still exist in use around the world today. One popular variant of the AKM is the AKMS, which features a folding metal stock instead of the fixed wooden stock of the AKM.

AK-56: This is a Chinese made variant of the AK family. While it is officially called the "Type-56", it is often referred to as the AK-56. Predictably, the number 56 indicates that the production of the Chinese models started in 1956. In the initial stages, the type-56 was a direct copy of the AK-47 type-1 model. However, in the 1960s, the Chinese incorporated some of the AKM improvements (e.g. stamped sheet metal receiver and slant compensator) and made some of their own modifications into their type-56 model, but did not change their version number for some reason. One visual difference between the AKM and the AK-56 is that the front sight of an AK-47 or an AKM is a partially open type, whereas the type-56 model has a fully hooded front sight.

Chinese sailor carrying a type-56 assault rifle. Click on image to enlarge. Public domain image.

The type-56 is the most prolific version of the AK family, since it was exported by the Chinese to various communist movements, especially in third world countries of Asia, South America and Africa. Nearly one in five (i.e. 20%) of AK type rifles in the world today is a type-56. When US forces were in Vietnam, the type-56 was found in enemy hands far more often than AKM or AK-47s.

AK-74: This was the next rifle that was officially adopted by the Soviet military in 1974. It was based on the AKM design. However, this variant fires 5.45x39 mm. ammunition instead of 7.62x39 mm. ammunition that the older variants fire. Because of this new cartridge, the barrel, receiver, magazine, firing mechanism, gas cylinder and sights are also altered to accommodate the new cartridge's dimensions. This rifle's magazine is made of a plastic, which makes it much more durable than the metal magazines of the AK-47 and AKM. The magazine shape is also subtly altered with two extra horizontal ribs, in order to make it impossible to insert it into an older AK model (since they don't use the same ammunition anyway). The pistol grip is made of a polymer plastic as well. Some early AK-74s have wooden hand guards and butt stock, but they use laminated wood instead of the plain wood that the earlier AK models use. Some later versions of the AK-74 use entirely polymer furniture (i.e. butt stock, pistol grip and hand guards) which is usually plum colored or black colored. The butt stock also has some cuts in it to reduce overall weight and also provide an easy way to distinguish it from an AKM.

AK-74 assault rifle. Click on image to enlarge. Public domain image.

Note the laminated wood stock with distinctive cuts on the side, laminated wood hand guards and the dark-brown plastic magazine.

There are also variants, such as the AKS-74, which feature folding metal stocks instead of wooden stocks, AKS-74U, which is a shorter carbine form of the AKS-74, AK-74M which features black plastic furniture completely (i.e. no wood parts) and has a mounting rail on the left to attach telescopic sight models etc. The firearm issued by the Russian military since the early 1990s is the AK-74M model, though earlier AK-74/AKS-74 still remain in service as well.

AK-74M assault rifle. Note the complete lack of wooden parts. Click on image to enlarge.

AK-101: This is a variant of the AK family that is meant for the export market outside Russia. That is why it is chambered to fire NATO standard 5.56x45 mm. ammunition, which is standard in many countries around the world. Naturally, the rest of the parts are also modified correspondingly. In short, the AK-101 is essentially an AK-74M design resized for the NATO cartridge.

AK-101 assault rifle. Click on image to enlarge. Public domain image.

Like the AK-74M, it also has a mounting rail on the side to allow attaching many optical devices that are common in Russia and Europe.

These are only a few of the models in the AK family of assault rifles. Unfortunately, many people in the media insist on calling all of them "AK-47s", in spite of the major differences between all the models. Surprisingly, true AK-47s are actually quite rare these days, especially the Type-1 variant. Most of what is referred to in the media as an "AK-47" is usually not the original AK-47 model, the weapon in question is usually a variant of AKM, a Type-56, an AK-74 etc. This became painfully apparent to the blog author when he attended a court case as a juror. The prosecutor kept referring to an assault rifle presented as evidence as "an AK-47". As the case progressed, it emerged that the firearm in question had a different firing mechanism as it was incapable of automatic fire (it could only fire in semi-automatic mode), had a laminated stock, used stamped parts and was made by an American manufacturer named Ewbank Manufacturing from Winslow, Arizona.

Shotguns: Why are shotguns used to break locks and why not other firearms?

2011-02-22T23:22:00.000-08:00

In many movies, there's a scene where the upstanding hero comes running around a corner, only to be confronted by a locked gate. No problem at all for the hero, he simply pulls out his trusty pistol and shoots one through the lock and then dramatically flings the gate open. Now, let's move on to real life scenarios: when we watch US forces in action in Iraq (or police on TV), there's usually one soldier carrying a M-16 rifle in his hands and a shotgun on his back. The shotgun is used to break through doors. So why do they carry such a heavier firearm if a pistol can do the job?

One of the reasons people use shotguns is because they can use special breeching rounds with them. We just studied breeching rounds two posts earlier. One of the advantages of breeching rounds are that the slug is designed to disintegrate on impact, so there's a far smaller chance of the round bouncing off or penetrating the door and accidentally injuring the shooter, a team-mate or an innocent bystander. That's very useful in confined areas and such. There are also other reasons, which we will study about here.

First thing the reader ought to learn is never believe everything you see on TV or in Hollywood movies. The first question is whether a pistol can actually penetrate through a lock. There was an interesting article on this subject posted earlier on theboxoftruth.com and we will merely post the summary here (visit the link for full details and pictures of the actual tests). The author of that article bought a bunch of laminated steel padlocks, similar to the one shown below:

These are fairly cheap locks (typically cost about $5-$10 each and cheaper if you buy six at a time) and very commonly used. Then the author of the article lined them all up and shot them from a distance of 15 feet. This was far enough so that they could avoid any ricochet problems. Note that Hollywood heroes never worry about such matters and usually shoot with the handgun held about a foot away from the lock, which is a darned stupid thing to do in real life.

In the case of handguns, the author tried using a 9 mm. pistol first (firing a ball and then a jacketed hollow point bullet), a .45 ACP (the all-american favorite!) and even a .44 magnum revolver (the Dirty Harry gun) with a jacketed hollow point bullet. In all the cases, the bullets just bounced off the locks, leaving minor dents. In the case of the .44 magnum, one pin was blown upwards off the lock due to the impact, but it still held just fine. So that's one Hollywood myth dealt with, now on to bigger weapons.

The author next fired at the locks with different assault rifles. First he tried with an AR-15 (the civilian version of the M-16), firing 5.56 mm. XM-193 ball ammunition and also Remington .223 soft point. The rifle bullets did penetrate fully through the lock, but they all left a small hole in front and a larger hole in the back and the pins all held. In order to fully open the lock, one would have to fire multiple times to break all the holding pins. The author also fired at a lock using a FN FAL using a .308 caliber Winchester round (i.e. civilian version of NATO standard 7.62x51 mm. cartridge) and also a .30 armor piercing round. In both cases, the rounds did blow the lower half of the lock off, but the upper part still had pins holding the lock closed. As with the AR-15, one would need to shoot the lock multiple times to unlock it.

Finally, the author tried shooting it with a 12 gauge shotgun (this is the most popular bore size for shotguns). Since the author didn't have access to breeching rounds, he tried using a Brenneke slug instead. Result: the shotgun simply blew the padlock body to pieces with the very first shot. and the padlock easily opened.

Conclusion: pistols and revolvers don't have what it takes to even penetrate a cheap, commonly used lock. Rifles will penetrate such locks, but do not reliably open the lock with a single shot. Therefore, one needs to take multiple shots at the lock to unlock it when using a rifle, which loses the element of surprise. Only a shotgun will reliably break locks with a single shot. Add to that the fact that ricochet risks are significantly reduced when using a special breeching round with the shotgun and the reader will see the reason why real soldiers and SWAT cops carry a shotgun with them, because nothing else will do the job!

Shotguns: Chokes and Choke Boring

2011-02-22T01:02:00.000-08:00

When a shotgun fires multiple pellets, they spread out in a cloud of pellets upon leaving the barrel. This is known as the shotgun pattern or shotgun shot spread. We've already studied how to determine the shotgun pattern earlier and the reader is advised to refresh their memory from the earlier article.

Now the key is that the largest number of pellets must penetrate in a 30 inch diameter circle, such that if a bird silhouette was to be placed on the circle, that the silhouette cannot be placed anywhere where at least 3 pellets are not going through it.

In order to increase the number of pellets within the 30 inch circle, a choke is often employed. Chokes may be built into the barrel, as part of the manufacturing process, or the end of the barrel may be threaded and the user can screw on a removable choke to the end of the muzzle as needed. This way, the user may be able to use different chokes depending on the number and diameter of the pellets used.

Since removable chokes are more modern, we will now study the history of choked barrels (i.e.) barrels manufactured with a built in choke.

The basic principles of choke-boring seem to have been invented by Spaniards, as we find the first mention of improving shooting patterns by various boring methods in Spanish books. M. de Marolles in his book, La Chasse au Fusil, states that some gunmakers in his time maintained that, in order to throw shot more closely, the barrel diameter should be narrower in the middle than on the breech or the muzzle end; while others insisted that the barrel must gradually contract from breech to muzzle. He goes on to describe methods to achieve these results, as were in vogue during his time. J.W. Long, an American author, in his book, American Wild Fowl Shooting, claims that choke-boring was an American invention and attributes the discovery to one Jeremiah Smith of Smithfield, Rhode Island, who was making choke-bored barrels, as early as 1827. The first known patent was granted to an American gunsmith, one Mr. Roper, on April 10th 1866, who preceded another claimant, an English gunmaker, Mr. Pape, by just six weeks.

While these early inventions were by American gunsmiths, they had not fully understood choke boring and therefore, a lot of their guns would lead, shoot irregular patterns and not shoot straight. It was left to an English manufacturer, W.W. Greener, to invent a method of choke boring that became the most widely used method in the later part of the 19th century. It was because of the popularity of the Greener method of boring that some authorities falsely give W.W. Greener the credit for inventing choke boring, though he himself never claimed to invent it.

W.W. Greener was a well-known gunmaker in Birmingham in the 19th century (the firm is still around today). His first intimation of a choke formation was from a customer's letter in early 1874. This customer had ordered a custom gun and in his special instructions to Greener, he described a choked barrel, though he did not specify its size or shape, or how it was to be obtained. However, W.W. Greener was intrigued enough to conduct many experiments to determine how to make the best profile and size of the choke for any given bore diameter. He also invented new tooling to make this boring possible. After many months of experimenting, he figured out how to make appropriate choke profiles for any bore of shotgun.

The Greener choke consists of leaving the barrel mostly cylindrical, but creating a constriction in the barrel towards the muzzle end of the barrel, as can be seen in the figure above. Before this method was invented, most people would either make the breech end of the barrel of a slightly larger diameter for up to 10 inches of barrel length from the breech, or they would bore the middle of the barrel to a smaller diameter and make the breech and muzzle of a larger diameter, or they would simply leave the barrel as a true cylinder (no choke).

On December 5th 1874, Mr. J.H. Walsh, the Editor of Field magazine, mentioned the Greener choke in an article, that read:
"We have not ourselves tested these guns, but Mr. W.W. Greener is now prepared to execute orders for 12-bores warranted to average 210 pellets of No. 6 shot in a 30-in. circle, with three drachms of powder, the weight of the gun being 7.25 lb. With larger bores and heavier charges, he states that an average pattern of 240 will be gained. As we have always found Mr. W.W, Greener's statements of what his guns would do borne out by our experience, we are fully prepared to accept those now made".

The article created a sensation because the very best 12-bore shotgun in the London public gun trial of 1866 could only generate an average pattern of 127. The very next issue of Field magazine contained an ad from W.W. Greener guaranteeing a pattern of 210 on his 12-bore guns. There was also a letter to the Editor in the next issue, from a reader of the magazine, confirming that his latest purchase from W.W. Greener did indeed meet this claim and more. Naturally, such statements created a huge controversy among gun manufacturers and readers, and the Editor of Field magazine was compelled to send a Special Commissioner to witness and verify the shooting of Greener guns. The Special Commissioner not only verified the claims, he actually got an average pattern close to 220 during his testing! After that, several other manufacturers claimed to be in possession of the same method of boring as W.W. Greener and therefore, the proprietors of Field magazine decided to conduct a public trial, the London Gun Trial of 1875, to verify various manufacturer claims. Greener-made choke bores won overwhelmingly in this trial, as well as the London trials of 1877 and 1879 and the Chicago trials of 1879 and led to the fame of his company spreading.

The Greener method of choke-boring was later adopted by other manufacturers and became the dominant form of choke boring. Modern chokes today are usually screwed on to the muzzle end of the barrel and slightly change the diameter of the muzzle in much the same way.

Shotguns: Ammunition

2011-02-20T23:15:00.000-08:00

Shotguns are designed to fire a wide variety of ammunition, generally more than other firearm types. We will look at the various types of ammunition in this post.

Before we start, the reader is advised to revisit an earlier article on bore/gauge of a shotgun, which will come in useful to understand some concepts discussed in this article. The reader may also find it useful to peruse the article on shotgun pattern testing.

The first, and most common type, is the shotshell. This is a cartridge that contains a number of pellets, usually made of lead, steel alloy, bismuth alloy or titanium composite. The most common type of shotshell is birdshot, which is commonly used to hunt birds. It consists of a cartridge containing dozens to hundreds of small pellets or ball-bearnings.

Public domain image

The shotgun shell is cylindrically shaped. In earlier days, the outer case was made of brass or thick paper. Modern shotgun shells are usually made of plastic with a thin hollow brass base cover, such as the illustration above. From left to right, we have the brass base of the cartridge, the propellant material (the gray part) which sits inside the brass base and extends out of it, a lot of wadding (the olive, pink and brown bands), the shot pellets and finally, another wad (the brown band on the right) that holds the shot pellets in the cartridge. The purpose of the olive, pink and brown wad is two-fold. First, it provides a gas seal between the pellets and the propellant. If it is not there, the propellant gas will simply flow through the gaps between the pellets instead of propelling the pellets. The second reason is that the wadding acts as a shock absorber or a cushion. When the shell is fired, the wadding gets crushed first and absorbs some of the shock. Without it, many pellets could get deformed by the propulsive force and thereby fly in the air erratically. The cushioning provided by the wadding prevents this.

The pellets in a shotgun shell are of uniform size. In earlier days, the pellets were mostly made of lead, using a process we described previously, because lead is cheap, easily formed and widely available. However, lead is a poisonous substance and can cause lead poisoning (e.g.) pellets that fall into ponds when hunters are hunting water birds. Water fowl could accidentally ingest some of these pellets and end up poisoned. Then, these could be eaten by birds of prey or animals and in turn, they get poisoned as well. People drinking the water could get affected too. These days, the environmental effects of lead are being taken more seriously and therefore, lead pellets are banned in several areas. Hence, modern pellets are now made of steel, bismuth or titanium composites.

Birdshot, like the name suggests, is used to hunt birds. Different gauges are used depending on the species of birds being hunted.

The next variation of shotgun shells use buckshot. These are similar to birdshot, except that the pellets are larger in diameter. Buckshot is designed to take down larger game animals, such as deer (which is why it got the name "buck" shot).

The next common variant is the solid slug. This is a single, solid, heavy bullet used to hunt large game. Many slugs already have rifling cut into them. The first design of a solid slug was from a German designer called Wilhelm Brenneke in 1898. His design has remained largely unchanged until now.

A Brenneke slug. Public domain image

The above image is of a Brenneke type slug. Notice the grooves cut into the sides of the slug. As before, there's a large amount of wadding (the white and brown parts) between the propellant and the slug. This kind is very popular in Europe and sometimes referred to as "European type" slug.

Another design is the Foster slug, designed by an American named Karl Foster in 1931. In this type of slug, there is a deep hollow inside, so that the center of mass is closer to the tip of the slug. This is designed for smoothbore barrels and because of the position of the center of mass, it doesn't tumble in the air because the drag causes the back of the slug to stay behind the front (much like a shuttlecock's feathers). This type is popular in the US and is sometimes referred to as the "American slug". It is also possible to fire this type of slug through a rifled barrel, but it causes lead buildup in the rifling grooves to happen at a faster rate.

Yet another type is the sabot slug. The word "sabot" comes from French, where it was used to describe a type of shoe worn by many workers during the industrial age. Incidentally, there was a period where the French workers went on strike, protesting their work conditions, and threw their sabot shoes into the industrial machines, hoping to jam them up. This is the origin of the word "sabotage"! In a sabot slug, the slug is usually an aerodynamic shape that is smaller than the barrel, surrounded by an outer shoe (the sabot) that provides a tight gas seal. The sabot gets deformed by the propellant pressures, while the slug inside is largely undeformed and intact. In case of rifled barrels, the sabot also has the rifling and therefore provides spin to the bullet. Once the bullet clears the barrel, the sabot separates from the bullet and falls down and the undeformed bullet continues on its way. This provides for better accuracy and faster velocity of the bullet. On the flip side, sabot slugs are more expensive and more time-consuming to manufacture.

The next type of shotgun ammunition is the bean bag round, also known by its trademark, flexible baton round. It consists of a small fabric container filled with birdshot. It is designed to be "less lethal" than the rounds we've studied so far. This type of round is designed to stun a person rather than kill them. Of course, fired at close range, it can be lethal as well. In longer ranges, it could be lethal if it strikes a vulnerable part of a person's anatomy, such as the throat or solar plexus. This type is typically used by police to incapacitate and capture a suspect. Other variations use rubber shot instead of bean bags for the same effect.

Another older form of the bean bag round was the rock salt shell. As the name suggests, shells were filled with rock salt crystals. Since salt crystals are brittle, these shells were not as lethal at longer ranges, but still caused a stinging bruise, enough to dissuade a person from attacking. These were used by police and rural farmers in earlier days.

Another type of shotgun shell is used for riot control. This is the gas shell and it normally contains pepper gas or tear gas.

Breaching rounds are often seen in use with police and military units. This is a special round designed to destroy door locks and door hinges, without endangering nearby bystanders. These rounds are also called Disintegrator or Hatton rounds. The slug is made of a dense metal powder, which is held together by a binder material such as wax. When fired at a door lock from close ranges, the slug destroys the lock and quickly disintegrates into a metal powder, instead of ricocheting somewhere or penetrating through the door. This is what makes is suitable to be used in tight confined spaces.

There are also other ammunition types, such as those that provide a lot of flash, or a whistling noise. These are used to scare or disorient animals, but are not lethal.

As you can see, there are many types of ammunition for shotguns, all for different uses.

Shotguns: Hammerless Shotguns

2011-02-16T22:17:00.000-08:00

In this post, we will look at a class of shotguns called "hammerless" shotguns. To understand hammerless shotguns, first let us look at a shotgun that has hammers.

The above picture shows a double-barreled shotgun. The hammers are the two roughly S shaped pieces you see in the image. To cock the shotgun, the user pulls back the hammers using the long spurs at the end of the hammer, until they lock when pulled back. Then the user applies a percussion cap to each of the brass nipples of the shotgun. When the user pulls a trigger, the hammer is released. Due to a spring attached to the hammer, the hammer strikes the percussion cap with considerable force, which detonates it and then discharges the firearm. This sort of design has existed since the earliest shotguns.

Now that we know what a shotgun with a hammer looks like, we will now look at a hammerless shotgun.

In the above picture, we have a hammerless shotgun. Note the absence of the two hammers near the open end of the barrels (the breech). The lever that you see behind the barrels is merely a lever that holds the barrels down when the shotgun breech is closed. So does this mean that this weapon has no hammers? Actually, this weapon does have hammers, but they are hidden inside the weapon. The word "hammerless" is a misnomer and it should really have been called "internal hammers".

Unlike the first shotgun we saw, which had external hammers (or exposed hammers), a hammerless shotgun actually has internal hammers, which are hidden inside the action, as shown in the figure below

In the above diagram, A is the hammer. In this above design, when the barrels are tilted downwards, the projection C rotates the hammer A backwards, against the pressure of spring B. The hammer A rotates until the lever D catches it and holds it in place, as shown in the picture above. When the user pulls the trigger, the lever D pivots and releases the hammer A, which then allows spring B to expand and makes the hammer strike the base of the cartridge, thereby discharging the shotgun.

One of the disadvantages of an external hammer is that the hammer spurs can get caught on items, such as clothing, small branches etc. and thereby cause accidents or failure to fire. With internal hammers, such an event is not possible.

The first hammerless shotguns came some obscure French and Belgian manufacturers in the early 1800s. In the 1830s, there was a hammerless shotgun developed by a Prussian gunmaker named Dreyse. We studied this gun when studying the side-motion action.

In here, turning the lever at the bottom, not only rotated the barrels around an eccentric path, they also cocked the two internal hammers.

The next advances were by an English gunmaker named Needham in 1856 and another English maker named Daw in 1862:

Needham Hammerless Gun from 1856. Click image to enlarge. Public domain image.

Shotgun made by Daw in 1862. Click image to enlarge. Public domain image.

In these versions, a long lever is placed in front of the triggers, as can be seen in the figures above. This lever can be pushed out to cock the internal hammers and eject the old cartridges and then folded back into place. Many of the early hammerless shotguns used a plan like this.

Of course, with such an approach, the user has to open the breech, then push the lever to eject the old cartridges and cock the gun, pull the lever back into place, then put in new cartridges and then shut the breech and lock the barrels into place, before firing the weapon. In order to make the whole process more efficient, some manufacturers attempted to reduce some of these steps.

During the period of 1875 to 1878, several London and Birmingham gunmakers attempted to make self-cocking guns, which would get cocked automatically upon opening the breech. The first successful hammerless action of this type was the Anson and Deeley action, which was invented in 1875 by two gunsmiths named Anson and Deeley, who were then working for the British manufacturer Westley-Richards and later formed their own company. They were followed by other British manufacturers such as Green, Scott, Parson, Rigby, Greener, Purdey, Walker etc. One such action working on these principles was already described above and we reproduce the illustration again so that the reader doesn't have to scroll up.

The basic Anson and Deeley design quickly became the dominant form of hammerless action and has remained almost unchanged to the present day. Since the original design had only 4 moving parts, it was cheaper and more reliable than other hammerless actions of its day, which contributed to its popularity.

In America, the first hammerless design was by Daniel LeFever in 1878. At that time, he was working with a partner named John Nichols in Nichols & LeFever Co. Like the early European designs, his shotguns had a separate lever to manually cock the shotgun. In 1880, LeFever formed his own separate company, the Lefever Arms Company. In 1883, he improved his hammerless design so that the separate lever was no longer needed. Unlike the European designs which would cock the internal hammers upon opening the breech, his 1883 design would cock the internal hammers upon closing the breech. He also later patented an automatic ejector which would eject the old cartridges when the breech was opened. In 1912, the Lefever Arms Company branched out into manufacturing gear boxes (selective and planetary transmissions) and jackshafts for the newly emerging automobile industry. Lefever Arms Company was an independent manufacturer until 1916, when the gear manufacturing side was merged with the Durston Gear Company and the firearms manufacturing side was bought out by the Ithaca Gun Company. The Ithaca Gun Company made some cheaper weapons using the LeFever name until 1941, but these weren't very good quality and were only exploiting the good reputation of the LeFever brand name. Original Lefever Arms Company guns from before they were bought out, still command high prices today and are regarded as some of the finest shotguns ever made in America.

"Hammerless" actions exist for other types of firearms as well. For instance, one can also find revolvers and pistols that have internal hammers.

Shotguns: Actions and Designs

2011-02-14T01:13:00.000-08:00

The early history of true shotguns begins in the 1800s, when people began to use them to hunt birds. During that time, the flintlock firing mechanism was the ignition system of choice and hence, it should be no surprise to know that early shotguns used them. The problem with such mechanisms is that there is a noticeable delay between pulling the trigger and the weapon actually discharging. The Rev. Alexander Forsythe, a Scottish clergyman and an avid hunter, noticed that the local birds would see the flame in the pan and immediately change direction and thereby escape. Hence, he set about inventing the percussion lock, which was the next big development in firearms technology and was also used by other firearms besides shotguns. The percussion lock was eventually replaced by modern cartridges, which we use to this day.

Shotguns come in both single barrel and double-barrel types. Double-barreled shotguns have two triggers, one to discharge each barrel. Of the double barreled shotguns, there are two types: "side by side" type and "over and under" type. What this means is how the two barrels are positioned. In "side by side" types, the barrels are placed beside one another, whereas "over and under" types have one barrel positioned on top of another.

"Side by Side" type shotgun

"Over and Under" type shotgun

Double barrel shotgun barrels are never attached parallel to each other, but instead set so that their shot will converge at some point (usually at 40 yards distance). In some shotguns, one of the two barrels may be made different from the other. For instance, one may have rifling and the other is smoothbore, or one barrel may be choked for closer shooting. In other cases, both barrels may be made as identical as possible.

Of all the actions, the break-open action, such as the two images above, is the most common type and has been around for a long time. This is a breech-loading mechanism. It was realized in 1875 that the movement of opening the action could also be used to cock the weapon at the same time. The first such cocking mechanism was pioneered by Anson and Deerley for their hammerless shotgun and it is still used almost unchanged to this day. Break-open actions are the most common type used for shotguns.

Another action that was invented in the mid 1800s and rare today, is the side-motion action. In this type of action, the barrels are mounted on the edge of a metal disc. A lever in the bottom of the stock rotates this disc, which causes the barrels to move in an eccentric motion, where they can be reloaded.

Another action that was invented in the 1800s, but is rare now, is the sliding barrel action shotgun. There are only a few manufacturers around that make this type currently and it was never as popular in the 1800s either.

Sliding Barrel Action Shotgun

Lever action shotguns were popular in the 1880s. The Winchester model M1887 was designed by John Browning and became a best-seller for the company. This was the first truly successful model of a repeating shotgun. This action allowed for users to load multiple cartridges into the weapon, not just one or two cartridges. Their popularity waned after the design that we're about to study in the next paragraph was introduced, and we don't see too many lever action shotguns these days.

Lever-action

The action that replaced the lever action design is the pump action shotgun design. The first popular ones of this type were the Winchester M1893 and M1897 models, which were designed by John Browning! It must be noted that when Winchester originally asked Browning to design a repeating shotgun in the 1880s, he had argued that a pump-action mechanism shotgun would be the most appropriate design, but Winchester was a lever-action manufacturing company, so they persuaded him to design a lever-action shotgun, which was the M1887 model described above. However, they did later manufacture his pump-action design as the Winchester model M1893, which was later improved to the model M1897. It must be noted that the M1897 shotgun gained so much popularity that it was used by US soldiers in World War I, where it was found very useful for trench fighting. Its quick shooting speed and the fact that the spread of buckshot could hit multiple enemies at once with minimal aiming, made it a very effective weapon for US soldiers to have. In fact, the German troops feared this weapon greatly and the German High Command even attempted to have it outlawed in combat, by citing Geneva convention laws (this coming from the same people that allowed the use of poison gas!). The pump-action shotgun design is still popular to this day.

Pump Action shotgun

There are also semi-automatic shotguns, where some of the force generated by the firing cartridge is used to eject the old cartridge, cock the action and load a new cartridge. Semi-automatic shotguns use a variety of mechanisms: long recoil action, inertia operated action or gas-operated action. The first successful semi-automatic shotgun was the Auto-5 (or A-5) action first designed in 1898 by (surprise, surprise) John Browning! The Auto-5 model remained in production until 1998!

Semi-automatic Remington Model 11 shotgun using long-recoil action

Bolt-action shotguns also exist in the wild, though they are not common. One particular model was manufactured in .410 caliber by the Ishapore arsenal of India, based on the Lee-Enfield SMLE Mark III model.

Ishapore .410 caliber bolt action shotgun. Click on image to enlarge.

In the next post, we will look into more about shotguns.

Shotguns: Basics

2011-02-03T23:02:00.000-08:00

In our last post, we looked at a type of firearm called the blunderbuss. These weapons faded out of popularity around the end of the 18th century. In the next few posts, we will study a descendant of the blunderbuss, the shotgun.

A shotgun is typically a shoulder-fired weapon of short range. The barrel is generally smooth, though some modern shotguns may be rifled as well. Shotguns typically fire a cartridge that contains a number of small pellets (shot) or a single solid projectile (slug). The ability to fire multiple shot pellets simultaneously is what distinguishes a shotgun from other firearms. The shot pellets spread out over an area upon leaving the barrel. The force of the burning propellant is divided among all these shot pellets and hence the energy transferred to any individual shot is fairly low.

Winchester model 1897, pump-action shotgun. Click image to enlarge. Public domain image from wikipedia.org

Shotguns were historically shorter than rifles and hence easier to manipulate in close quarters. However, they had much more power than pistols, since they were designed to be supported from the shoulder. For this reason, they were traditionally used by cavalry and coachmen as a close range defensive weapon. In previous centuries, banks would send money in stagecoaches and the person sitting next to the driver would carry a large shotgun with him. This is the origin of an American slang term that still exists to the present day: "riding shotgun". For non-US readers of this blog, this slang term means the person who's sitting on the front passenger seat next to the driver in a modern automobile. A common tradition observed in the US: when a group of friends are planning to travel together somewhere by automobile, the first person who yells "shotgun" upon seeing the vehicle that they are travelling in, gets the privilege to "ride shotgun" (i.e.) sit in the front passenger seat.

Shotguns were also traditionally used to shoot birds and small fast-moving game animals (such as rabbits, hares etc.) Because these offer small targets and move very rapidly, it is difficult to aim at them exactly. Since a shotgun fires multiple shot pellets which spread out over an area, it is not necessary to aim as precisely when using a shotgun. We already discussed how to measure how the shotgun spreads its shot out in an earlier post.

Shotguns are also used by military and police as short-range weapons, especially useful in trench warfare, urban combat and riot control situations. The shotgun has been in and out of military use throughout history, but the US military rediscovered its usefulness around World War I and it has remained in use since then. The picture below shows some US Marines in action in November 2005. Note that the Marine in front is carrying a shotgun.

Public domain image. Click on image to enlarge.

Shotguns are also very popular for home-defense use because of the spread-out nature of shot (i.e.) it is not necessary to aim accurately, which comes in useful if there is a break-in at night. A shotgun fired in the general direction of an intruder results in multiple wounds to the intruder, which is likely to incapacitate him or her. However, since each individual pellet has lower power than a rifle, it is less likely to penetrate the walls and injure a neighbor or a bystander. A shotgun also looks more intimidating than a pistol or revolver. Additionally, the distinctive click sound of a shotgun being cocked is often enough to deter many would-be burglars.

Shotguns typically come in a number of calibers, from a small .22 caliber shotgun to massive punt guns. They take a variety of ammunition types: shot pellets, solid slugs, bean bags and rubber bullets (for riot control and non-lethal use), tear gas or pepper spray (for riot control), breaching rounds (for destroying door locks and hinges) etc. We will study all these types of ammunition as we study shotguns in future posts.

Blunderbuss

2011-01-27T23:02:00.000-08:00

A blunderbuss is a short range defensive weapon that reached its popularity in the 18th and 19th centuries. We will study this unique class of firearms in this post.

A typical blunderbuss is a muzzle-loader with a relatively short barrel that has a distinctive trumpet-shaped flare at the muzzle end of the barrel. The caliber of this weapon is typically large and it was often used by filling the barrel with multiple smaller pellets.

A Blunderbuss. Note the typical flared muzzle end of the firearm.

The original term for this weapon was donderbuss and this name appears to be Dutch. The word "donder" means "thunder" and "buss" means "pipe" in Dutch and German languages. Blunderbuss class weapons also appeared in handgun form, intended for cavalry. These early pistol blunderbusses often had decorations around the muzzle that looked like a dragon with an open mouth and hence were called "dragons". The cavalrymen who used such blunderbuss pistols were therefore called "dragoons". One such example of a dragon pistol is shown below:

The trumpet shape at the muzzle is the distinctive blunderbuss feature that distinguishes it from other firearms of that period. Since a blunderbuss is designed to fire several pellets at the same time, the flare was thought to increase the spread of pellets. The flare also makes it easier to load powder and pellets into the firearm. People mounted on horseback, or in a rocking coach or ship, found this feature very useful indeed. Also, since these are shorter weapons compared to the muskets of the era, they are more easy to manipulate on horseback or a ship deck. This is why they were very popular among cavalry, pirates, mail coach guards, naval personnel etc.

Blunderbusses designed for navies and pirates typically had their barrels made of brass instead of iron, to prevent rusting. Since they are designed to spread multiple pellets around, one such shot could easily deal with several closely packed enemies with a single shot. Hence, they were often carried into action by boarding personnel.

While most blunderbusses were designed as everyday practical weapons, some blunderbusses were also works of art:

Blunderbuss commissioned by Tipu Sultan of Mysore, India. Click image to enlarge.

Image licensed under the Creative Commons Attribution-Share Alike 3.0 Unported License by UploadAlt at wikipedia.com

The above weapon was custom made for Tipu Sultan, who ruled the Kingdom of Mysore in the 18th century. This fine weapon uses a flintlock firing mechanism and the barrel has engravings and gold inlays. Tipu Sultan was known to employ several European craftsmen and this weapon represents the latest in technology of that period.

As breech-loading weapons became more common in the 19th century, the blunderbuss gradually became obsolete and was replaced by the carbine.

What is a Bullpup Rifle?

2011-01-24T23:19:00.000-08:00

In most rifle configurations, the trigger is located right underneath or very close to the the firing action. This means that the barrel starts right about where the trigger is. This has generally been the standard configuration for most firearms ever since firearms were invented. However, in the beginning of the 1900s, the concept of having a trigger ahead of the action was invented. This type of action is called a bullpup design and we will study about this type of design in this post.

Steyr AUG A1 rifle, one of the first successful bullpup designs.

Image licensed from Steyr Mannlicher GmbH & Co. under the Creative Commons Attribution 2.0 License/

Since the bullpup design has the trigger in front of the action, this means that the action sits close to the back of the buttstock and closer to the user's face. That means the overall length of the weapon is reduced. Also, since the stock contains part of the barrel and the action, the stock is much smaller and hence, a bit lighter than a conventional rifle. For example, the Steyr AUG rifle that you see in the image above has a 20 inch long barrel and uses 5.56 mm. NATO caliber cartridges, but is only 790 mm. long and about 3.6 kg in weight. By comparison, a conventional configured rifle, such as an M16A2, also has a 20 inch long barrel and uses 5.56 mm. NATO caliber, but is 1010 mm. long and 4 kg. in weight, which means that we save about 25% in length and about 10% in weight with a bullpup configuration.

The original bullpup design was invented in England in 1901. The Thorneycroft carbine was chambered for a .303 rifle cartridge and held five rounds in an internal magazine. It was 7.5 inches shorter and 10% lighter than the standard Lee Enfield rifle, which was the standard infantry arm of the British military and also fired a .303 cartridge. The Thorneycroft rifle suffered from recoil and ergonomics and was not adopted for military service. Later inventors tried to improve the design, such as a couple of French inventors in the 1920s and 1930s, but were not widely accepted. The Enfield factory came out with the EM-2 after World War II, but since it was not designed for NATO caliber, it faded from use very soon after. However, the British did not forget the concept of a bullpup configuration and later designed the L85 assault rifle in 1985, which is the current standard British military firearm.

Public domain image of a British L85A1 assault rifle

However, it wasn't the British that came out with the first successful bullpup configured rifle. That honor goes to the Steyr AUG which came out in 1977. The Steyr AUG was adopted by Austria initially and was later adopted by over 25 countries. Unlike previous attempts, the Steyr AUG was highly reliable, light and accurate and showed off the advantages of a bullpup configuration. France followed soon after with their new standard infantry rifle, the FAMAS, in 1978. This was followed by the UK's L85A1 and L85A2 models in the 1980s and early 1990s. Soon, many other countries followed suit, such as the Chinese QBZ 95, Singapore's SAR-21 and the Israeli Tavor TAR-21.

While bullpup designs are shorter and lighter (and therefore easier to maneuver in confined spaces), there are a few disadvantages as well. One of the early ones is that the ejection port of the rifle sits a lot closer to the user's face. Since most rifles eject spent cartridges to the right, left handed shooters have to shoot right-handed style to avoid getting a hot cartridge to the face. Some assault rifles (such as the Steyr AUG and FAMAS) get around this issue by allowing the user to easily swap the bolt and ejection cover around, so that left handed users can make the rifle eject to the left. Other rifles solve this by ejecting the spent cases forwards or downwards. Other issues with bullpup configurations are that the noise appears louder as the firing chamber is closer to the user's ears and magazine changes take a little longer, due to the ergonomics of this configuration. On the other hand, with the success of the Steyr AUG, many other militaries have also adopted rifles with bullpup configurations, because of the lighter and shorter nature of such designs.

Testing Firearms: Extreme Torture Test

2011-01-23T00:09:00.000-08:00

In the last post, we studied some of the criteria that militaries follow when selecting a new firearm for their inventory. Among the extensive list of selection criteria is a set of torture tests, which test the firearm for reliability, functionality and ease of use under demanding conditions. While military tests are pretty demanding, they are not necessarily the toughest tests that a firearm may be subject to.

A few years ago, one enterprising gentleman decided to conduct a series of tests to determine exactly how reliable his Glock model 21 pistol was. He fully documented his process and even took video footage to prove that he'd actually conducted the tests.

The entire series test is documented here. The first couple of pictures in his original post seem to have disappeared, but a backup copy of that legendary post was also archived here, with the first few pictures intact. Note that the second link only has pictures, but not the links to the movies, which the first link contains. It is a very interesting read. The tests he conducted seem to be even more demanding than military tests. Bear in mind that this particular pistol was almost 10 years old already and had been well used and abused, before he even started conducting the tests. Also, half-way through the torture test process, he took the very same weapon to a weekend gun match!

While this is an extreme case of mistreatment, it is interesting to note that his weapon still managed to function after all that had been done to it. Note that the gentleman conducting the tests is a professional expert and such tests should NEVER be conducted by readers of this blog.

Testing Firearms: Military Acceptance Tests for Handguns

2011-01-21T21:07:00.000-08:00

In the history of firearms, the most stringent requirements are usually applied when a weapon is selected for military use. This is because military weapons:

Should be able to work in demanding conditions (snow, heat, rain, dirt etc.)
Should be reliable, extremely resistant to damage and have long service life.
Should have good range and stopping power.
Should be simple to service in the field.
Should not be too expensive, because a large number of them will be ordered.
Should perhaps maintain compatibility with some other existing system (e.g. use cartridges of a specific caliber, be under a certain size to fit into vehicles, have at least a certain magazine capacity etc.)

The weapon that is selected by a military strikes a balance between these various factors. In this posting, we will look at some historical selection criteria for handguns from various regions around the world.

The first set of criteria we will look at is the requirements of the US Army in 1906 for a new handgun. A few years earlier, US Army units in the Philippines had discovered that the standard Army revolver at that time, a revolver chambered in .38 Long Colt cartridge, was not sufficient to stop a charging Moro tribesman high on narcotics. With that in mind, the US Army Ordinance Department (headed by Colonel John Thompson, who later invented the Tommy gun), did some experiments and determined that a .45 caliber cartridge had the stopping power needed. Therefore, one of the first requirements of the new handgun was that it should be able to shoot the new .45 caliber cartridge. The US Army also subject all submitted handguns to the following torture tests:

Each gun was to fire 6,000 rounds.
Each gun would shoot 100 rounds at a time and then allowed to cool for 5 minutes before shooting again.
Every 1,000 rounds fired, the gun was to be oiled and cleaned before firing again.
After firing 6,000 rounds was completed, the gun was to be tested with deformed cartridges (i.e.) some that seated too deeply, some that were not seated enough etc.
The gun would be exposed to acid to test rust resistance, buried in sand and mud to test reliability etc.

Designs were submitted by Colt, Luger, Knoble, Bergmann, White-Merrill, Smith & Wesson and Savage. The Colt entry was designed by the renowned designer John Browning. The Browning design easily passed all the tests and became known as the M1911 pistol (as it was accepted officially in 1911). In the words of the selection committee:

"...the board was of the opinion that the Colt is superior, because it is more reliable, more enduring, more easily disassembled when there are broken parts to be replaced, and more accurate."

Now we will look at some of the requirements for the Austrian military in 1980, when selecting a new firearm. The Austrians were looking for a handgun to replace their old World War II era Walther P38s. Among the criteria specified:

The design has to be self-loading (i.e.) it should load a new cartridge automatically after an old one is fired.
The weapon must fire the NATO standard 9x19 mm. parabellum round (same as the old Walther P38)
Magazine of the weapon should not require any means of assistance for loading.
Minimum capacity of the magazine should be 8 rounds.
All actions necessary to prepare the pistol for firing and any actions required after firing must be done single-handed, either right or left-handed.
Pistol must be secure from shock. Tests to be conducted by dropping the pistol from a height of 2 meters onto a steel plate from various angles.
Pistol should allow for disassembly and reassembly of the main parts, without using any tools.
Maintenance and cleaning of the pistol should be done without tools.
Pistol should not have more than 58 parts (which was the number of parts on the Walther P-38)
Gauges, measuring and precise testing devices must not be necessary for long term maintenance.
All components must be interchangeable with other pistols
No more than 20 malfunctions are permitted during the first 10,000 rounds fired.
After 15,000 rounds, each pistol will be inspected for wear and tear. The pistol will then fire an over-pressured test cartridge generating 5,000 bar (72,518 psi) which is almost 2x the pressure generated by the standard NATO 9x19 mm. parabellum cartridge (which only generates 2,520 bar (36,500 psi)). The critical components must still continue to function properly after firing this over-pressured cartridge.
When handled properly, under no circumstance should the user be endangered by case ejection.
The muzzle energy of the bullet should be at least 441.5 Joules when firing a 9mm. S-Round/P-08 Hirtenberger AG cartridge.

While there were submissions by many well known firearm manufacturers, it was the design by a then unknown firm called Glock that won this contest. Interestingly, since Glock had no previous firearm design experience, the Austrian authorities decided to subject it to the 10,000 round test with no more than 20 malfunctions. To everyone's surprise, the Glock design only suffered one malfunction in 10,000 rounds. None of the other manufacturers' submissions were subject to this grueling test because it was simply assumed that the others would pass as well!

Other torture tests included testing under extreme heat, ice, sand and mud and testing the firearms both after oiling and in an unlubricated state etc. They also considered other factors such as the time taken to train new shooters, number of parts to manipulate to make the weapon ready to shoot and ease of maintenance. Glock's design not only passed these tests with flying colors, they were far ahead of any other competing pistol, while also being 25% cheaper than the next lowest bidder. Glocks have since been accepted by many other militaries and police forces around the world.

Testing Firearms: Shotgun Pattern Test

2011-01-17T22:46:00.000-08:00

People who use shotguns for hunting birds often use ammunition that contain multiple pellets or ball bearings. When such a cartridge is shot, the pellets spread out about a certain area, depending on the distance to the target. The pellets leave the shotgun in approximately the same order that they were in the cartridge and continue in a compact mass, until they hit a target, or fall on the ground. In order to reduce the area of concentration of the pellets, people employ various devices on the barrel such as a cylinder choke, skeet choke, modified choke, full choke etc. Of course, different choke types work differently with different ammunition types and hence testing is needed to determine the most effective combinations.

The standard way to test the shotgun pattern is to take a square sheet of paper around 40-45 inches long on each side. The tester mounts this sheet of paper at a distance of 40 yards. The tester then loads the shotgun with a cartridge that has a known number of pellets and shoots at the target. After this, the shooter looks at the paper and draws a circle of 30 inches diameter around the area with the greatest concentration of pellets.

Then the tester counts the number of holes inside this 30 inch circle. Say there are 150 holes inside the circle and the tester knows that the cartridge had 200 pellets loaded. Therefore the tester can say that this shotgun shoots with a 75% pattern for this choke and cartridge load combination.

The tester repeats this test five or more times with a given cartridge load and computes the average to get the shotgun pattern. Obviously, the type of choke used, the number and size of the pellets in the cartridge and the material of the pellets all may have an effect on the pattern density, so the tester tries the same test out with different combinations to find out which of these produce the best patterns.

In order to keep the tests accurate, one needs to make sure that the cartridges used in this test have the same number of pellets or ball bearings each time. One way to do this is to weigh the pellets before loading them into the cartridge. The following table illustrates the average number of pellets per ounce of different standard pellet sizes for both lead and steel pellets:

Of course, this assumes that the pellets are all of the same shot size. Some people don't believe in weighing the pellets to get a count. Instead, what they do is use a simple counting device, such as the one shown below:

Public domain image. Click on image to enlarge.

It consists of a flat trowel made of brass or steel, with a number of holes drilled into it. There is a sliding cover on the handle that can be used to vary the number of holes exposed on the face of the trowel. The tester pushes the trowel into a pile of pellets or bearings and slowly withdraws it. Pellets will stick to the holes and those that are not in any holes can easily be separated. Any misshapen or undersized pellets are also easily visible, so they can be removed as well. The tester can thus easily load the exact same number of pellets into multiple cartridges.

Testing Firearms: Machine Rests

2011-01-16T23:08:00.000-08:00

When testing firearms and ammunition for accuracy and range, it is necessary to minimize human error as much as possible. When a human being shoots at a target, it is human nature that there is a lack of consistency between shots. A person may hold the firearm tighter or looser, shake the firearm more or less, vary the trigger pull force and react to the recoil differently from shot to shot. In order to eliminate variability for these factors, the industry developed machine rests (a.k.a bench rests). We will study these in this post.

A machine rest should ideally have the characteristic that it simulates a human shoulder or arm, so that it absorbs the recoil from a firearm as though a human were holding it. This is very important because if the machine rest is completely fixed, it will result in damage to the firearm's stock, bedding or recoil lugs. The machine rest should also be able to return back to zero (i.e.) back to its previous position before firing it. There should be some provision to pull the trigger by mechanical means, so that the trigger pull force and speed are consistent between shots. Some machine rests also have gauges to record the recoil force generated by the firearms as well.

In the above image, we have a machine rest designed in the 1890s, which was used by Field magazine to evaluate various firearms. It was made of iron, so that it was relatively portable. Points of interest are the spring balance H and toggle joint I. The spring balance records the recoil force and the toggle joint ensures that the varying strength of the spring at different positions is equalized out to provide a constant resistance. The device J, which is located under the stock of the rifle is an oil reservoir which has a cylinder and piston. This returns the firearm slowly back to its initial firing position, after it has been discharged.

Here's what a typical modern machine rest for rifles looks like:

This particular modern rifle rest is made by Hyskore and has interchangeable shock absorbers (compression dampers) for different rifle types. In this particular model, the shock absorbers are filled with nitrogen gas. It also has various knobs to adjust elevation and windage precisely and aim the rifle to the target. In addition, it has a remote controlled hydraulic trigger pull, so that there is consistency between one trigger pull and the next.

Next, we will look at another well known brand of machine rests used for handguns:

The above is a Ransom International made rest, which is pretty much the gold-standard when it comes to accuracy testing of handguns. Ransom International introduced the Master Series Rest into the market in 1969 and the Master Series models are still being sold today. In fact, most major handgun manufacturers use this model for accuracy testing. Like the other rests, this also simulates the grip and recoil absorption of a human hand very closely and it also has the facility to return the firearm back to its initial position after the shot. The trigger is activated by a little lever on the side, to provide consistent trigger pulls each time.

While major manufacturers use machine rests to ensure quality control of their products, these are also used by owners to evaluate their firearms and ammunition brands. For example, ammunition from different manufacturers come in different qualities. A tester can shoot X rounds each from different brands and determine which ammunition manufacturer produces cartridges that shoot uniformly best. Also, many new semi-automatic pistols have a tendency to shoot the first cartridge in the magazine in a different place than the other ones. Using a machine rest allows a tester to evaluate if a particular pistol has this characteristic. Some revolvers sometimes have some chambers in the cylinder that shoot at a different point than the rest of the chambers. Using a machine rest allows the tester to mark out which chamber(s) shoot differently and perhaps not load those chambers.

Testing Firearms: Bullet Penetration

2011-01-16T02:49:00.000-08:00

One of the tests of cartridges is the penetration test. This test shows how effectively a particular type of bullet will penetrate its target. As we studied earlier, there are different types of bullets: hollow point, full-metal jacket, soft-point etc. There are also different types of targets: For example, a bullet shot at vermin such as rats, needs to expand really quickly after it hits the target, to have any effect on the animal. It should not exit out the other end without expanding first. However, the same bullet will not be as effective on a larger animal, if it expands too early, as it will not hit a vital organ and not ensure a quick kill.

Penetration testing in earlier years used to involve using thick brown paper sheets or strawboards. These were stacked together horizontally and shot at, and the count of the number of sheets or boards penetrated were tallied up and compared to each other. The following image shows one of these test racks

Public domain image. Click image to enlarge.

In modern times, the medium of choice is a material called ballistic gelatin. The reason for using ballistic gelatin is because it has about the same density of human or animal tissues. Ballistic gelatin is also preferable to actual muscle tissues, since its properties can be more carefully controlled to produce a consistent medium for doing multiple comparative tests. It must be noted that ballistic gel doesn't completely simulate actual body structure, since it doesn't have any skin or bones, which are much tougher and harder than flesh tissue.

The standard formula used for testing is called "10% ballistic gel". It consists of mixing 1 part by mass of powdered ballistic gel formula with 9 parts of water at a temperature of 54.5 C (130 F). The mixture is poured into standard molds (per the INS National Firearms Unit test, the standard mold size is 6" x 6" x 16" for handguns. Other standards bureaus may have different standard test sizes) and the mixture is chilled to 4 C (39 F) and allowed to set.

Before conducting the actual tests, the gel block is initially calibrated by firing a standard 4.5 mm. steel ball bearing from an air gun, over a chronograph and into the gel block. The air gun should shoot the ball bearing at a velocity of 183 ± 3 meters/sec. (600 ± 10 feet/sec.), which can be verified by the chronograph. If the gel block was prepared correctly, the penetration of the ball bearing should be between 8.3 to 9.5 cm. (3.25 - 3.75 inches). If this is the case, then the gel block may be used for standardized testing.

In most police agencies, testing teams usually test for penetration in other materials as well: gelatin, heavy clothing, steel, particle board, plywood, automobile glass etc.

For homebrew testers who don't have access to ballistic gel, people generally use wet newspaper blocks or wet phone books or a line of 1-gallon jugs filled with water.

Testing Firearms: Measuring Bullet Velocity - III

2011-01-14T00:37:00.000-08:00

In our last post, we studied a few methods that measure the time taken by the bullet to travel a known distance and thereby calculate its velocity. These methods fall under the class of chronograph methods. All these methods were generally inferior to the ballistic pendulum method for a variety of reasons, chiefly the inability to measure small amounts of time accurately and also the inability to ensure that the targets were moving at uniform rates.

While the ballistic pendulum method was superior for a long time, one of the issues it had was the weight of the apparatus. For testing the velocity of ordinary rifles or shotguns, the ballistic pendulum alone needs to weigh around 25 kg. (55 lbs.), without considering the weight of the supporting frame. When people try to scale this method for larger cannon balls, the weight of the pendulum apparatus increases exponentially. For example, in 1781, one Mr. Hutton tried to measure the velocity of cannon balls weighing just 3 pounds and his pendulum weighed about 315 kg. (approx. 700 lbs.). During the period of 1842 to 1847, one Major Alfred Mordecai from the United States Army tried to determine the muzzle velocity of larger guns and built a ballistic pendulum weighing over 4215 kg. (approx. 9300 pounds) and was mounted between two large brick towers. This could only measure velocities for 32 pounders at most. It was estimated that to build a ballistic pendulum to measure velocities for even larger weapons, one would need to build a massive pendulum suspended by the two Brooklyn bridge sized towers!

Meanwhile, the discovery of electricity made chronograph methods much more accurate. It was now possible to measure the beginning and end of a period of time using some sort of electrically operated mechanism. It also became possible to measure very small intervals of time accurately, making chronograph methods much more accurate than was achievable previously.

One of the early chronoscopes was invented by Charles Wheatstone, a noted scientist of the Victorian era. Among his other inventions were a stereoscope, an encryption system, several developments in telegraphy and the wheatstone bridge. His chronoscope consisted of a wooden ring fixed to the muzzle of a gun, with a thin wire running through the middle of it. The target was placed at a known distance and consisted of two plates which were arranged so that the least impact would result in a permanent contact between the two plates. The wires were hooked to an electromagnet mechanism and a small battery. Initially, a continuous circuit would be maintained. Then when the firearm would be discharged, the bullet would leave the muzzle and pass through the wooden ring and cut the thin wire running through the center. This would deactivate the electromagnet, which would then start a special clock driven by a falling weight. When the bullet would hit the target, the second circuit would be completed, which would re-energize the electromagnet and stop the clock. This mechanism was capable of measuring time with a resolution accurate to approx. 1/7300 of a second, which allowed it to calculate bullet velocities very accurately.

A more modernized version used a tuning fork to measure small increments of time. The tuning fork would have a thin stylus attached to one of the arms and a roll of paper would be gradually moved over the stylus. The tuning fork would be activated and deactivated by electricity and the tester would count the number of vibrations of the tuning fork, inscribed on the paper roll, to determine the elapsed time.

Using electricity to measure time became much more popular because the same setup could be used on just about any caliber firearm.

These days, modern chronographs use optical detection or to determine the passage of a bullet through a known distance. For instance, photo-transistors (such as those that work with infrared frequencies) could be used to start and stop a highly accurate stopwatch. The passing bullet shadow causes the circuit to be activated and deactivated at the two ends of a known distance and very high time resolutions can be obtained. Such devices are pretty cheap as well and available for around $100-$200 or so.

In the above images, we have a modern chronograph that can measure bullet velocities between 30 - 7000 feet/sec with 99.5% accuracy. The V arms indicate the area through which the bullet should be shot for the sensors to detect it. The two white strips on the top are light diffusers, so that this device can be used even in bright sunlight. They also help to provide a uniform background so the photo-transistor sensors can easily detect the contrast a passing bullet. In less than bright daylight conditions, the two diffusers can be optionally removed. The digital display automatically calculates the bullet velocity, so all the user needs to do is position this device on a flat surface, such as a table, turn it on and then shoot through the two V areas. High velocity rifles should be shot from at least 3 meters (10 feet) away and lower velocity weapons may be shot from around half that distance to get accurate readings.

Modern chronographs such as the one above make it a breeze to calculate bullet velocities. Due to their lightness and low cost, these are overwhelmingly the method of choice to measure bullet velocities these days.

Testing Firearms: Measuring Bullet Velocity - II

2011-01-11T22:14:00.001-08:00

In our previous post, we studied the first accurate method of identifying bullet velocities: the ballistic pendulum method. While the ballistic pendulum method was accurate and remained in use for many decades, it wasn't initially adopted all over Europe perhaps because the inventor was English. Instead there were some other methods developed in some other countries of Europe, all of which were developed after the ballistic pendulum method. Some of these were not as accurate, but were still preferred over the ballistic pendulum method, perhaps because of nationalistic reasons. The interesting thing about these methods is that while they were more inaccurate than the ballistic pendulum method at the time they were invented, they laid the foundations for more modern and accurate methods of determining bullet velocities.

In 1767, an Italian named Mattei came up with a method to measure bullet velocities. His method consisted of a vertical paper cylinder which was mounted on a wooden frame. The frame was made to rotate by using a cord and a weight. Once a uniform known speed was attained by it, the bullet was fired through it, perpendicular to the axis of the cylinder. The bullet passed through the paper cylinder and left two holes on the surface. The two holes gave the arc through which the cylinder had rotated as the bullet passed through it. By computing the length of the arc and knowing the diameter and the rotational speed of the cylinder, one could compute the bullet velocity. However, this method's precision was dependent on three factors: (a) the diameter of the cylinder, (b) knowing the rotational speed accurately and (c) the uniformity of the rotation. This machine was also not very effective against faster moving bullets, because it could not measure times less than 1/30th of a second, during which time a modern bullet, such as that fired by an M-16 rifle, could easily cover 100 feet (30 meters), which means you'd have to use a cylinder at least 100 feet in diameter to measure the speed of an M-16 bullet reasonably. It was also very hard to make sure the cylinder was rotating uniformly and so the device was not very accurate either.

In 1804, a French officer named Colonel Grobert invented another method to determine bullet velocity based on similar principles as Mattei's method. In Grobert's method, two large disks about 6.5 feet in diameter, made of cardboard, were attached to the same horizontal axle. In Grobert's original design, the two disks were placed 13 feet apart. The axle was rapidly rotated by means of an endless chain in combination with a flywheel and a windlass. When the rotation of the axle was judged to be at a constant speed, the tester then aimed at the disks and fired a shot through them. The bullet pierced through both disks, but since they were rotating rapidly, the exit hole through the second disk was not in the same line as the exit hole through the first disk. By looking at the positions of the two holes, one could determine the angle of revolution. Since the distance between the two disks was known and the speed of rotation was also known, the tester could calculate the bullet velocity. However, this method had the same weaknesses as the Mattei method described above.

The next step to correct these above problems was invented by another French officer, one Colonel Dabooz, in 1818. His method involved a gravity apparatus to measure bullet velocities.

His apparatus consisted of two screens, two pulleys, a cord and a counterweight. In his method, a fixed screen was placed precisely 50 yards from the muzzle of the firearm to be tested. Directly in front of the fixed screen was another screen, which was suspended by the cord. The cord passed through two pulleys and the other end was right in front of the muzzle of the gun and was tied to a counterweight, which held the movable screen in place. The firearm was aimed at the screens. When the firearm was discharged, the bullet would cut the cord as it left the barrel. This would release the movable screen, which would start falling. The bullet would travel 50 yards and pass through both screens. Since the movable screen was falling during this time, the hole in the movable screen would not be at the same height as the hole in the fixed screen. Knowing the acceleration due to gravity and measuring the distance between the holes in the two screens, the tester could calculate how much time the bullet took to travel 50 yards and from this, he could calculate the bullet velocity. This method had the advantage that a constant acceleration was imposed on the falling screen (since acceleration due to gravity remains constant), which made the time measurement more reliable. To measure the velocities of faster moving bullets, the distance between the two pulleys could be increased and reasonably accurate measurements could be made. The one error in this method is that it assumed that the movable screen would begin to fall as soon as the bullet passed through the cord.

The reader might note that while these three method use different ideas, they have one thing in common: they all measure the time taken for a bullet to travel through a known distance and from this, they determine the bullet velocity. This is unlike the ballistic pendulum method, which uses the principle of conservation of momentum to determine the bullet velocity. While these methods were not as accurate as the ballistic pendulum method when they were invented, they laid the foundation for the concept of cronographs. With the invention of electricity, the cronograph concept became more practical and more accurate and it eventually replaced the ballistic pendulum method. We will study practical cronographs in the next post.

Testing Firearms: Measuring Bullet Velocity - I

2011-01-10T22:19:00.001-08:00

In our previous posts, we've seen how to measure chamber pressures and trigger pull force. In this post, we will study how to measure bullet velocity. This will be a study in two posts since there is much to discuss on this topic.

First, why does someone need to know the bullet velocity. For one, it is useful to compute the kinetic energy carried by the bullet. We can obtain the bullet mass by weighing it and if we can obtain its velocity, then its kinetic energy is computed by simple mathematics: kinetic energy is calculated as (0.5 * bullet mass * bullet velocity). Also, it is useful to know how much velocity a bullet loses over distance to determine effectiveness over various distances.

The first really good method to determine the bullet velocity appeared in a book published in 1742 called New Principles of Gunnery written by Benjamin Robins, an English mathematician with an interest in ballistics. This was a very influential book, as it introduced military men to the teachings of Newtonian physics. This book also contributed to the development of artillery towards the end of the 18th century and was responsible for introducing calculus to the syllabus of many military academies. In fact, Benjamin Robins is considered one of the founders of modern aerodynamics and the father of modern gunnery. Before this book appeared, gunnery was simply a matter of guesswork. After this book was published, it became an exact science. The work was so influential that the famous Swiss mathematician and physicist, Leonhard Euler, himself translated this book into German.

In this book, Robins introduced the concept of a ballistic pendulum. In his original book, this is a heavy iron weight with a wooden board covering its face. The bullet is fired into the pendulum weight and gets embedded into the wooden board. The act of the bullet hitting the pendulum transmits the bullet's momentum into the pendulum, causing it to swing, as shown in the image below:

Public domain image

The pendulum also has a ribbon attached to the arm and gripped loosely by a clamp. As the pendulum swings, it pulls a length of ribbon out with it. By measuring how much of the ribbon was pulled out, we can determine the length of the pendulum's arc. We can also measure how many times the pendulum swings in one minute (i.e. its oscillation period).

An image of the original apparatus as published in Benjamin Robins' book, New Principles of Gunnery

Click on image to enlarge.

Robins' original formula used the oscillation period and mass of the pendulum and the pendulum arm to calculate its rotational moment of inertia and from there, the bullet's velocity. In his original work, he ignored the effect of the bullet not hitting the center of mass of the pendulum weight. The very next year, an updated formula to correct for this omission appeared in a paper published by the Royal Society of England. Meanwhile, Leonhard Euler, who was unaware about the corrected formula, independently determined the same corrected calculation and published the corrected version when he translated Robins' book into German. The formula is computed as:

v = 614.58 * g * c * (p + b) / (b * i * r * n)

where:

v = Velocity of bullet in meters/sec
g = Distance from the pivot to center of gravity of the pendulum in meters
c = The chord (i.e.) length of swing of the pendulum determined by the ribbon in meters
p = Mass of the pendulum in kg.
b = Mass of the bullet in kg.
i = Impact point (i.e.) distance from the pivot to the point of impact of the bullet in meters
r = Radius (i.e) distance of the pivot to the point of attachment of the ribbon in meters
n = Number of oscillations made by the pendulum in one minute

The same formula can be switched to get velocity in feet/sec and if one uses feet instead of meters and pounds instead of kg.

If one were to ignore the effects of rotational inertia (whose effect is somewhat small to begin with) and ignore the mass of the pendulum arm (modern day materials technology can make the pendulum arm very lightweight compared to the weight of the pendulum), this formula can be simplified even further as:

v = ( 1 + p / b) * sqrt(2 * G * h)

where G = acceleration due to gravity and h = height of the pendulum's travel and the other terms are the same as the previous formula. If the simplified formula is used, one doesn't even need to calculate the pendulum's period of oscillation and it is sufficient to only weigh the bullet and the pendulum and measure the height of the pendulum's travel. Of course, this simplified formula doesn't provide as accurate an answer as the first formula, but is good enough for many calculations.

This simple experiment was the first really scientific method to determine bullet velocity and the book that it was published in revolutionized military science. This method remained in use for quite a while into the mid 1800s before becoming obsolete. However, it is still seen in high-school physics labs, to teach the concepts of momentum and velocity.

Testing Firearms: Measuring Trigger Pull Force

2011-01-09T22:11:00.001-08:00

The term "trigger pull force" is defined as the amount of force that is needed to cause the trigger to release in a firearm. If a firearm has a very light trigger pull a.k.a. a hair trigger, then it can be shot very rapidly, as it takes very little force to activate the trigger. However, it also has a greater chance of accidentally discharging, because of the same reason. On the other hand, if a firearm has a very heavy trigger pull, the user will not be able to shoot rapidly and will also not shoot accurately, because the force of pulling the trigger will usually cause the user to shake the firearm a bit more.

So how does one measure trigger pull force. Well, if one is a gadget junkie and has money to spend, then one could acquire a trigger pull gauge like the two examples below:

The first is a mechanical spring gauge, much like an old fashioned spring balance and the second is a digital gauge. To measure the trigger pull force, the tester cocks the weapon (making sure it is unloaded first), simply fastens the hook end to the trigger and pulls the gauge backwards until the trigger releases the firing mechanism. The reading then shows how much force was needed to release the trigger. The illustration below shows how this is done.

Then there is another simple technique as the image below shows. This one is from a Life Magazine issue from 1937, but the same technique is used to this day in many official shooting competitions.

The tester simply adds weights until the trigger releases. Simple and easy to perform.

Before the reader assumes that this is an outdated method, this technique is still used in official NRA shooting competitions to make sure that no competitor is shooting with too light a trigger.

The above image is an NRA official trigger weight system and is available from some sporting goods stores.

Of course, for the casual user who doesn't want to spend $50-$100+ for gizmos like the ones above, there is a much more lower tech way of measuring the trigger pull force, which gives fairly accurate results as well. The homebrew tester simply acquires some heavy wire, such as a wire clothes hanger, cuts it to length and bends it into a S-shaped hook, using a pair of pliers.

The tester first unloads the gun and makes sure it is empty and then cocks the trigger. Then the tester simply hooks the trigger to the large end of the S-hook and then hangs a plastic shopping bag or a tin can from the small end of the S-hook. The tester then adds weights to the plastic shopping bag until the trigger releases. Then the tester employs an ordinary weighing scale (such as the one used in kitchens) and weighs the hook, the plastic bag and its contents. Multiplying this mass with the acceleration due to gravity gives the trigger pull force.

For testers who don't have access to weighing scales, they simply load the plastic shopping bag with known weights, such as grocery items. For instance, 500 gm. bags of beans, 100 gm. boxes of cocoa powder etc. can be loaded into the plastic bag until the trigger pulls. The weight of the S-hook and the plastic shopping bag and the bags that various grocery items come in are considered to be of somewhat negligible compared to the weight of the groceries themselves, so this method can give pretty good approximate results. For example, using 500 gm. bags of beans, it may be possible to determine that the release point of a certain firearm is between 2 kg. and 2.5 kg. (i.e. between 4.4 and 5.5 pounds) because the trigger didn't release when four 500 gm. bags of beans were in the plastic bag, but adding a fifth one did. Then the tester resets the experiment, adds four 500 gm. bags of beans back into the plastic shopping bag and then starts adding 100 gm. cocoa powder boxes until the trigger releases, at let us say 2.3 kg. Now the tester knows that the trigger release point is between 2.2 and 2.3 kg. Then the tester can repeat the experiment using four bags of beans, 2 boxes of cocoa powder and something else that weighs say 20 gms. etc. to get more accurate results and so on.

Testing Firearms: Measuring Chamber Pressures

2011-01-09T00:51:00.000-08:00

In this post, we will look into the technique of measuring pressures inside a barrel, when a firearm is discharged. It is important for people to determine pressures of a firearm with various types and brands of ammunition, because some ammunition may produce too much pressure and therefore cause the firearm to explode. A system that enables one to determine the pressure is therefore very useful to determine which ammunition types may be safely used by a firearm.

The maximum pressure is exerted at the breech end in the firing chamber and decreases further down the barrel tube. That's why published numbers usually only list the chamber pressure. It must be noted that there are a couple of different standards in exactly how the pressure is measured. In our first post about proof testing, there were two organizations mentioned, CIP and SAAMI, that publish firearms data. Unfortunately, they have slightly different ideas about how chamber pressures should be measured. We will study these differences a little while later down in this post. Suffice it to say that CIP doesn't care about the shape of the cartridge when deciding which point to take the pressure reading from, whereas SAAMI has different locations to measure the pressure from, based on the shape and diameter of the cartridge. Therefore CIP and SAAMI numbers don't match up for this reason.

The classic method of measuring pressures goes back to the 1800s and early 1900s. It was the method most in use until about the 1960s. It uses crusher gauges to determine pressures.

It consists of a device that allows mounting of a gun barrel. The gun barrel is drilled at various points where pressure measurements are desired. To each of these holes is pushed a tight fitting stopper and the other end of the stopper is held in place by a precisely machined cylindrical piece, which in turn is supported by a steel screw. The precisely machined cylindrical piece is of uniform density and made of copper or lead, depending on the firearm type. For lower pressure weapons such as shotguns or smaller pistols, a lead cylinder is used, whereas copper cylinders are used for higher pressure applications such as rifle or most handgun cartridges. When the cartridge is fired, some of the gas pushes upwards and drives the stoppers out of their holes. This has the effect of squeezing the copper (or lead) cylindrical pieces against the steel screws holding them in position. The amount of deformation of the copper or lead cylinders is measured very precisely and compared with a chart of similar cylinders which were deformed previously under known pressures and the corresponding value is called the Copper Unit of Pressure (CUP) or Lead Unit of Pressure (LUP) value.

While CUP or LUP values are meant to be compared with the crushing power of a known pressure, this is not always the case. For example, the same amount of deformation can occur from a short duration high-pressure pulse as from a longer duration, but lower pressure pulse. Also, these numbers tend to be a bit lower than peak pressures measured using transducers. Therefore, when measurements are made using crusher gauges, the pressure is listed in mega-pascals (MPa - the SI standard unit of pressure) or pounds per square inch (psi - the imperial standard unit of pressure) followed by the letters CUP or LUP to indicate that the measurements were done using crusher gauges.

The crusher gauge method was the only reliable method of measuring chamber pressures until the 1960s, when cheap piezoelectric devices became available. This method is called the Conformal Transducer method or Piezo method. A piezoelectric transducer (a.k.a. sensor) has the property that it generates electricity as it is crushed. The setup is similar to the crusher gauge method, except that instead of a copper cylinder, a quartz crystal transducer is used. Quartz is a material that exhibits piezoelectric properties. Thus, when the cartridge is fired, the transducer transmits electricity, which can be measured and then compared against values generated by similar transducers, when subject to known amounts of pressure. This method has the advantage of measuring pressures at different instants of time, as the bullet leaves the barrel. Measurements by this method generally read about 15-20% higher than those shown by the crusher gauge method. As piezoelectric sensors have become much cheaper now, this is the method of choice for measuring chamber pressures, though crusher gauge measurements are still around as well.

Here's where the differences between the CIP and SAAMI standards show up. CIP uses a transducer made by the Swiss firm Kistler and requires a hole be drilled into the cartridge case and fired by a specially prepared barrel. SAAMI uses a different transducer, called a conformal sensor, mostly made by a US Company PCB Piezotronics. These sensors don't need holes drilled in the case, but they are more expensive as each one needs to be designed based on the diameter of the cartridge.

CIP standards state that the transducer should be positioned 25 mm. from the breech face, when the cartridge is long enough. If the cartridge is too small, then CIP decides to position the transducer at a shorter distance from the breech face, based on the cartridge model. CIP standards do not care what the shape of the cartridge is.

SAAMI, on the other hand, does care what the cartridge is shaped like. For bottle-necked cartridges, the center of the transducer is placed 0.175 inches (4.4 mm.) behind the shoulder of the cartridge for large diameter (0.250 inches, 6.4 mm.) transducers and 0.150 inches (3.8 mm.) behind the shoulder of the cartridge for small diameter transducers. For cylindrical cartridges, the transducer is located behind the base of the seated bullet at a distance of (0.5 * transducer diameter + 0.005 inches)

Since the two standards have different methods and different points from where to take measurements, therefore the CIP and SAAMI pressure numbers are different from each other for the same cartridge type.

Using a transducer is less expensive than using crusher gauges because the same transducer can be reused over and over again, as long as the cartridges used are the same type. So if a tester wants to repeat the test multiple times to get an average pressure reading, he or she only needs one transducer, if using the piezo method. Compare this to the crusher gauge method where each test needs a new copper cylinder and the costs begin to add up.

The third method involves using a strain gauge. This is a thin, flat piece of wire whose electrical resistance changes as it is stretched or strained. The strain gauge is attached on the outside of the barrel near the front of the chamber. When the firearm is discharged, the barrel expands slightly, which stretches the strain gauge and the change in the electrical resistance can be measured and the pressure calculated. This method is fairly accurate, but not as reliable as the other two methods. However, it has the advantage of being the cheapest method of the three and not requiring as much special equipment as the other two methods.

It must be noted that no test can give a truly accurate pressure reading because there is no way to know what the actual pressure should be. Even if the tester uses 100 identical cartridges with equal amounts of propellant and using the same firearm and test setup, the tester can expect up to a 5% variance in pressure values from cartridge to cartridge, when using the crusher gauge method to measure pressure. With the conformal transducer method, the variance is up to 3% from cartridge to cartridge. This is why the conformal transducer method is proclaimed as more accurate than the crusher gauge or the strain gauge method.

Testing Firearms: Proof Test - II

2011-01-06T23:54:00.000-08:00

In our last post, we studied all about proof testing and how it is carried out these days. The reader may also find it of interest to learn how it was carried out in the late 1800s and early 1900s as well. In this post, we will study how testing was done in England during this period, as the tests conducted there were generally regarded to be of high-quality.

It was discussed in our previous post that all firearms that were sold in England had to pass the tests of either the London Proof House or Birmingham Proof House. Even though these two proof houses had different proof-marks, the test procedures they used were identical.

The test procedures specified what types of propellant and bullets and their quantities would be used for testing, depending on the type of firearm being tested. For instance, in the early 1900s, the standard propellants specified for the various tests were powders of the following brands: "Tower Proof", Waltham Abbey's "RFG No. 2" with grain sizes between #4 and #5, Curtis's & Harvey's "TS No. 2", "Colonel Hawker's Duck-Gun Powder" and cordite. Bullets were to be of pure lead, except in the case of rifles where nickel plated bullets were to be used. In the case of shotguns, pellets of size #6 were to be used in the test.

Each manufacturer would deliver firearms to be tested, to a proof-house (either London or Birmingham) in an unmarked condition. The first task at hand was to attach each firearm with a unique identifying number. This ensured that the manufacturer of any particular firearm would be unknown to the testers conducting the tests, so that they would have no opportunity of spoiling the test results if they had a previous prejudice against any particular manufacturer.

The next step was to send the firearms to be tested into a gauging room. This is where the bore of the barrel would be determined. In this room, each tester was equipped with a set of 50-60 gauging plugs from the size of a pea to a couple of inches in diameter. Each tester would determine the exact bore of a barrel using these plugs and then pick up a corresponding steel punch and stamp a number on the barrel corresponding to the plug number that best fit the barrel.

After this, the firearms would be transported a short distance to a loading room. This room was divided into three compartments with very strong brick walls in between, so that in case of an accidental explosion, the damage would be confined to a particular compartment. To minimize casualties in case of accident, only necessary personnel were allowed into these rooms. The floors of these rooms were always kept well swept to ensure that there wouldn't be any loose gunpowder lying around. The floors were also always kept damp for extra safety. In the first compartment, a workman would have a set of numbered copper measuring flasks on a rack. The workman would look at the number stamped on the barrel from the gauging room and pick up the corresponding copper measuring flask and fill it with gunpowder. The measuring flasks were pre-calibrated to charge the barrel with extra gunpowder, depending on the bore of the barrel and how much overcharge was specified by the test procedures. After filling a barrel with gunpowder or an overcharged cartridge, the tester would then add a wad to the barrel and pass it through a small window into the next compartment. In the second compartment, a second workman would fill it with bullets specified for the particular barrel type, then ram the charges home with a copper rod and then pass it to the third compartment. In the third compartment, a workman would prepare the barrels for firing (i.e.) add priming powder or a percussion cap depending on the firearm type.

The prepared firearms would now be moved into the firing room. The firing room was a strongly built building lined with sheet iron and had ventilators that could be operated from outside. The door of this room was also made of iron and the room was designed to contain powerful explosions. Depending on the type of firearms, different proof tests would be carried out (a Provisional Proof Test and a Definitive Proof Test). Some firearm types only required one test (the provisional proof test), but most required both tests to be carried out.

As was mentioned in the previous post, a Provisional Proof Test is a test that is carried out in the early stages of the firearm manufacturing process. It is usually conducted for shotgun barrels, though other firearm types may also have this test. The idea behind a provisional proof test is to discover defects in the barrel early on in the build process, so that the manufacturer does not waste time continuing to build a firearm around a weak barrel. The Definitive Proof Test is generally conducted on a fully assembled firearm and tests the strength of barrel and firing action together.

In the case of the provisional test, the barrels to be tested would be lined up on a grooved rack. A thin line of gunpowder would be poured in a groove in the back, that connected all the barrels together. The thin line of gunpowder would be fired by using a hammer striking a percussion cap and the hammer would be operated from the outside of the firing room. On both sides of the barrels were large heaps of sand to collect all the bullets and ensure that there would be no ricochets. The tester would line up the barrels, leave the room, close all the vents and the door and then pull the firing mechanism trigger from the outside. The thin line of gunpowder would ignite and therefore fire each barrel in sequence. After each barrel in the train had fired, they would open the ventilators and allow the smoke to clear. The barrels would be collected from the room and those that had not fired were reprimed and placed back on the rack. The other barrels would be taken to an inspecting room, where they would be washed and inspected for flaws. In the case of "common barrels", they would be allowed to stand for 24 hours before washing, because any flaws in the barrels would become more obvious by the action of the acid residue of the gunpowder eating into them. All barrels that had no visible flaws would be stamped with the appropriate markings to show that a provisional proof test was done.

Provisional Proof Test conducted by Birmingham Proof House.

Taken from W.W. Greener's The Gun and Its Development Edition from 1910

Click on image to enlarge.

In the case of definitive proof tests, the test would be conducted with the barrel and its firing action attached to it. The definitive proof test was carried out individually for each firearm (unlike the mass-testing for the provisional test). Each firearm would be fired by using a thin thread to manipulate its firing mechanism from the outside of the room. The definitive proof test verified the strength of the barrel as well as the firing action. With the definitive proof tests, barrels that failed would either burst or suffer bulges. Bulged barrels would be returned to the manufacturer to readjust and resubmit for proof. It is said that in one case, a particular barrel was tested and bulged eight times, before passing on the ninth attempt! Firing actions that failed the definitive test would either blow up to smithereens or stay open at the area where the action meets the barrel. In the second case, the manufacturer would hammer the action back closed and case-harden it and resubmit for proving. Any firearms that fired the test charge successfully would then be taken to the inspecting room and cleaned and then examined for any flaws in the barrel or action. All firearms passing this test would be stamped with appropriate markings to indicate that a definitive proof test was done.

After the tests were passed, the firearms would then be sent back to the main receiving room, where the attached unique identifying numbers would be used to sort the firearms by manufacturer and then they would be shipped back to the manufacturers' factories. Only then would the manufacturers finish the firearm (i.e.) attach a quality stock, add engraving, stamp the manufacturer logo on it, adjust sights etc.

To give an idea of the scale of testing involved here, the Birmingham Proof House was equipped to conduct roughly half a million proof tests every year, during the 19th century. During the period 1804-1815, Birmingham manufacturers produced 3+ million firearms with an average failure rate of 2 per 1000 tests.

The proof test procedures conducted in England were of such a high standard that, in most other countries, the authorities would allow importers to sell all firearms with English proof markings without requiring any testing from their own proof-houses!

Testing Firearms: Proof Test

2011-01-05T23:40:00.000-08:00

The first type of testing we will study is the Proof Test. The idea behind such a test is to verify the strength of the barrel, breech and firing system of a firearm by deliberately firing an over-pressured cartridge. After this, the firearm is examined to make sure it is still intact and if so, the metal (usually the barrel) is stamped with one or more "proof marks" of the testing agency. The proof marks create indented impressions on the metal surface, so they cannot be accidentally removed. Such a test certifies that the firearm is free from manufacturing defects and will not explode under normal usage conditions. In many countries, proof tests are compulsory; and it is not possible to sell a firearm unless it has been proof-tested by an approved testing agency.

Some manufacturers in the town of St. Etienne in France started conducting proof tests around the 15th century, when firearms manufacturing started in that area. However, France didn't enact a law to make the test mandatory until the 1900s and hence, it was left to each French manufacturer to decide what the test standards should be or even whether to perform a test or not. In other areas, such as London and Birmingham in England and Liege in Belgium, even before testing became compulsory, most manufacturers used to do private tests in their own factories or in a trade testing house.

Compulsory testing laws were passed in most countries mainly due to the backing of the gunmaker guilds of those countries. By enacting such laws, the guilds sought to prevent the manufacture of firearms and stifle competition from non-guild members, even though they claimed that such laws were designed to protect members of the public. The first such compulsory law was passed due to the lobbying efforts of the London Gunmakers Company (a guild composed of firearm manufacturers around London). The initial bylaws passed by the London Gunmakers Company charter of 1637 marked the first introduction of proof tests in England, but didn't specify an official standard of testing. By 1672 though, they managed to get an enhanced law passed, so that agents of the London Gunmakers Company could legally search premises and run proof tests on any firearms made in London or suburbs within 10 miles, or firearms made of imported foreign parts, or firearms brought into London for sale. In order to enforce a standard, the London Gunmakers Company established the London Proof House which was staffed by employees of the various manufacturers comprising the guild. It wasn't coincidence that most barrels failing the proof test requirements were those made by gunmakers who were not members of the London Gunmakers Company guild (to be fair, most of these were often of much lesser quality than London made guns). On May 10th 1672, Maximilian Henry of Bavaria passed a law that made proof testing compulsory in Belgium and established the Liege Proof House to enforce this law. In Birmingham, most reputable manufacturers had their own private proof facilities and many of them also made their facilities available for use by others, but since proof testing was not compulsory in Birmingham, cheaper manufacturers didn't bother to do this test. After a lot of lobbying by the reputable Birmingham manufacturers, the Birmingham Gunmakers Company was finally formed in 1813 by an act of Parliament and authorized to create its own Birmingham Proof House (which still exists to this day in the same historic building). The Birmingham Proof House conducted the exact same tests as the London Proof House, but had different proof marks to indicate that the tests were done in Birmingham rather than London. The firearms manufacturers in Birmingham benefited by this Act because it was more convenient and faster for them to send their firearms locally to be tested, instead of sending them all the way to London. However, the initial Act passed in 1813 proved insufficient, as many less-reputable manufacturers found legal loopholes to evade it, so another Act was passed in 1815 and in 1855, both of which were also ineffective. Finally in 1868, a suitable Bill was passed which remained in force for a while. This Bill was actually a private Act and not a Statute law and specified that the members of the Birmingham Company would elect their own guardians to enforce the proof test standards. It was also enacted that any person making or selling a barrel that was not proved in either the Birmingham Proof House or the London Proof House would be subject to a fine for each violation and any person forging the proof-marks would be subject to a fine as well and defaulting on payments would result in more severe punishments such as imprisonment, confiscation of assets etc. The English proof test procedures were amended in 1888, 1893, 1896, 1904, 1925, 1954, 1978, 1986, 1989 etc. to account for advances in firearms technology. Thus it became impossible to sell firearms in England that were not proved by either of these two proof houses. Oddly enough, there was no similar compulsory law enacted for any of the British Colonies around the world!

Even though Belgium had also made testing compulsory since 1672, the standards of the Belgian tests were far inferior to the tests conducted in England for a long time. In 1892, Germany also made proof testing mandatory and adopted a standard that was essentially the English standard with minor modifications. Since the German standard was so similar to the English standard, the German authorities automatically approved any firearms with English proof marks with no further testing, but rejected any firearms with Belgian proof marks until they were re-proven in Germany. Since Germany was a major export market for Belgian manufacturers, the Belgians promptly adopted the higher standards by 1893. During this period, there were proof houses in other European countries as well, such as St. Etienne in France, Wiepert and Ferlach in Austria, Budapest in Hungary etc., but as proof testing was not mandatory in these countries, marks from these proof houses were not as well regarded as those of Belgium, Germany or England.

The types of proof tests applied depended on the firearm being tested. Factors such as muzzle loading or breech loading, whether the barrel has rifling or not, bore of the barrel etc. all determine the type and number of proof tests to be run. In the case of multi-chamber firearms, such as revolvers, each chamber would have to be individually proof tested before the firearm was marked. Each proof house had its own marks based on the type of tests applied to the firearm. These proof marks would be stamped on to the barrel of the weapon, usually on the underside so that they would normally not be visible unless one disassembled the weapon for cleaning. The following picture shows some of the proof marks used by different countries:

Click on the image to enlarge.

In general, there are two types of proof test: The first is the provisional test which is done mainly on shotgun barrels and is done during the early stages of manufacturing, so that the gun-maker does not waste time continuing to build a gun if the barrel tube is defective. The second is the definitive test which is conducted on a firearm that is completely assembled (or close to completion). It tests the strength of the barrel and the firearm action together.

Depending on the types of tests, one could see multiple proof marks on a single weapon, such as the following:

From left to right, the different marks tell us several things about this firearm. First, the left most icon indicates that a Provisional proof test was run on it and this was administered by the Birmingham Proof House (because of the crown with stylized BP lettering under it). The next mark (12/1) tells us that the weapon is of 12 bore. The next two marks indicate that two additional definitive tests were run on it by the Birmingham Proof House, a Proof test (crown with BP) and a View test (crown with BV). The diamond shape with 12 C on it and the word choke next to it indicate that this is a 12 bore weapon with choke-bored barrel.

The above image shows another weapon with proof marks left to right indicating: Provisional proof test run by London Gunmakers Proof House (Lion sitting on top of stylized GP), this is a 12 bore weapon (because of 12/1 mark), two more definitive proof tests were run by the London Proof House, a View test (Crown with V) and Proof test (Crown with GP). The diamond icon with 12 LC indicates that this is a 12 bore choke bored weapon and the R. Choke mark indicates that the barrel not only has choke-boring, but also has rifling in it.

The meaning of the proof marks for other countries were similarly organized, as the illustration below shows:

Indian Proof Marks

For example, the presence of a nitro-proof marking indicates that this firearm was also proved using newer smokeless nitro-powders.

These days, there are three main standards for proof testing: the C.I.P test and SAAMI test are for commercial firearms and the NATO EPVAT test for military firearms.

The CIP standard was established in 1914 in Liege, Belgium and ratified by law in 14 member countries (most of which are European) and it is illegal to sell civilian firearms in the member countries without having CIP proof marks from an accredited proof house. CIP also independently publishes data about ammunition dimensions, max. pressure generated by different ammunition types, max. pressure that can be tolerated by different firearms, testing procedures, compatibility between firearms and ammunition combinations etc. The current CIP member countries are Austria, Belgium, Chile, Czech Republic, Finland, France, Germany, Hungary, Italy, Russia, Slovakia, Spain, UAE and UK. In a standard CIP test, a firearm is fired twice with overloaded cartridges that produce 25% more pressure (30% more pressure for pistols, revolvers and weapons using rimfire cartridges) than the standard cartridge it would normally be fired with. After firing two overloaded cartridges, the firearm is disassembled and examined for magnetic flux leakage through fluoroscopic lamp in a dark room. If it passes, the CIP proof marks are stamped on to the metal, along with marks that indicate the date and the lab that performed the tests and the accompanying paperwork details are completed as well. Only then is the firearm sent back to the manufacturer or seller, who can now officially sell the firearm. Every civilian firearm that is for sale in a CIP member country is required by law to pass the tests, whether the manufacturer or seller is from a CIP member country or not. CIP also approves all ammunition that is sold by a manufacturer or importer in a CIP member country. The ammunition manufacturers are required to test each production lot in their factory against the CIP pressure specifications, document the test results and stamp each cartridge box with a CIP approved number that allows them to trace any quality-control problems back to a specific factory and lot number.

Similarly, in America, the SAAMI association (Sporting Arms and Ammunition Manufacturers' Institute) was founded by a group of American firearm and ammunition manufacturers in 1926 at the behest of the US Government and is an accredited standards developer for the American National Standards Institute (ANSI). SAAMI performs tests on weapons intended for the civilian market. SAAMI also publishes several technical documents, such as a list of Unsafe Arms and Ammunition Combinations which details cases where a smaller cartridge (e.g. a .44 magnum cartridge made by company X) could fit in a firearm designed to accommodate a larger cartridge (e.g. a .45 caliber pistol made by company Y), but would be unsafe to use because the cartridge produces higher gas pressures than what the firearm is rated for. Due to differences between SAAMI and CIP test procedures, there are some differences in pressure rating values for the same firearm and cartridge models and some combinations may be listed as unsafe in one standard and safe in the other. One more difference is that while the SAAMI association requires its member companies to follow the guidelines and product standards that it sets, it is not a compulsory standard enforced by any branch of the US government (unlike the CIP tests, which are required by law to sell a firearm or ammunition in a country that is a CIP member). All major American ammunition manufacturers are members of SAAMI and most smaller companies also follow its guidelines, except for a few smaller manufacturers. SAAMI also has other committees, such as one that works with CIP to develop common international standards, wildlife conservation, standards for transport and regulation of firearms etc.

The NATO EPVAT test standard is for military grade firearms. This is a much more comprehensive set of procedures than CIP or SAAMI and uses much more sophisticated test instruments.

Proof tests were instrumental in protecting the end-user from weapon failures and compulsory enforcement of these laws helped reduce firearm-related accidents around the world. This is why they are still mandatory in many countries.

Testing Firearms

2011-01-05T23:12:00.000-08:00

With the new year, we will now study another branch of firearms tech. Before we start, I would like to thank all the readers of this blog for their continued support and kind comments and wish you a very happy and productive year ahead.

With that said, we will now deal with the subject of testing. There are several tests that can be done on firearms, which we will study in the following series of posts. Broadly speaking, there are a few different categories of tests that are done with firearms:

Strength and pressure tests: These test the strength of the weapon to resist heavy pressures, test the pressures at the chamber of the weapon, test the pressures generated by different types of propellants, how much force is needed to pull the trigger etc.
Shooting properties tests: These test accuracy of a weapon over various distances, speed of the bullets, depth of penetration of the bullet, behavior of bullets upon hitting the target, force transferred upon impact, how many pellets hit a target per square inch for shotguns etc.
Reliability tests: These test the weapon against various usage conditions, e.g. under cold weather, humid conditions, dirty and muddy conditions, user who doesn't clean his weapon often etc.

We will look into various testing methods in the following days.

Concealed Weapons

2010-12-31T21:37:00.000-08:00

In our last post about combined firearms, two of the examples (the whip pistol and King Henry VIII's mace) are also examples of a concealed firearm. Well, technically, Henry VIII's mace is a weapon anyway, even though it conceals pistols within it. We also looked at derringer pistols earlier, which were designed to be concealed. In this post, we will look at some firearm designs that were designed to be hidden and give the illusion that the user had no means of self defense.

The first class of weapons we will look at is the firearm-cane class. Canes or walking sticks are often used by elderly people as a walking aid for hundreds of years. In the 19th and early 20th century, they were also seen as a fashion accessory that was popular with the gentlemanly class, whether young or old. For many centuries, people have concealed objects in canes. For example, there are stories of spies hiding messages in hollow walking sticks and an enterprising missionary to China smuggled silkworms to the west inside his hollow walking stick. Prince Edward, son of Queen Victoria, even commissioned a cane which had a hidden flask of whiskey within it, as well as a built-in hidden compass on the top of the cane knob, so that he could find his way home after a night of drinking!

The Japanese had the Shikomizue and the Romans had the Dolon, both of which concealed swords within a hollow walking stick. In the 18th and 19th centuries, sword canes also became popular with the wealthy classes of Europe. In the 19th century, people soon began to conceal firearms within canes as well. Such weapons were made by many English and European manufacturers:

The above example fires .410 caliber shotgun shells. The trigger is a foldable one and may be kept hidden, when not in use.

The above image is a cane made by Briggs of London in the 19th century. It conceals not only a sharp dagger, but also a 4-cylinder pepperbox revolver that fires .22 caliber ammunition.

These days, canes that contain concealed weapons are illegal in many countries, but some countries have a clause that they can be legally sold if they are over 100 years old. Therefore, older weapons are often seen in auctions.

The next weapon we will look at was invented by a Frenchman named Jacques Turbiaux in 1882. It was called a Palm Pistol:

This is a weapon designed to be concealed within one's fist and can be fired by squeezing the spring loaded lever in the back of the gun. The cartridges are loaded in a rotating turret with the bullets facing outwards. There were two version, a 7 shot version using 8 mm. cartridges, like the image shown above, and a 10 shot version using 6 mm. cartridges. The lever has a double action operation, in that it rotates the turret to the next shot, before firing it. Turbiaux obtained an US patent in 1883 and the Minneapolis Firearms Company produced a licensed version that fired 7 shots in .32 caliber. These weapons are typically rare today and sell for about $1500-2000 dollars in auctions.

In modern days, people have sought to conceal firearms in various guises. The following three pictures are some examples that were developed by spy agencies of various countries:

The first weapon is designed to look like a tire-gauge, but also fires a .22 caliber cartridge. It was supposedly used by CIA agents in the 1950s and 1960s. The next is a weapon designed to look like a camera, but carries a pistol within the lens. The third looks like a typical briefcase carried by a businessman, but hides a Hecker & Koch MP-5 submachine gun within it. It is fired by a hidden trigger concealed in the carrying handle of the briefcase.

Concealed weapons like these are illegal in most countries around the world, so the only concealed weapons these days are manufactured by intelligence agencies or custom built for criminals and are not available to the public. In fact, most of these designs are kept secret. Some countries allow certain concealed weapon items to be legally bought or sold if they can be classified as "antiques", so some historical items, such as pistol canes and palm pistols, are seen in auctions.

Combined Firearms: Other Weapons

2010-12-30T00:45:00.000-08:00

In the last few posts, we have seen firearms combined with axes, with swords and knives and with daggers. In this post, we will look at some examples of firearms combined with other weapons.

The first ones we will look at are available for display in the Historisches Museum in Dresden, Germany.

What we have here are a pair of German-made spear heads dating from around 1560. Each spear-head has two pistols, one on each side of the head. The pistols are powered by wheel-lock mechanisms, which the Germans were very good at producing, due to their expertise with clocks and clockwork mechanisms. Note that the first spear head is also very heavily decorated indicating that it was built for a rich customer. The first spear head also has a note that says it was built by one Peter Peck of Munich.

The next set of weapons may be seen in the armory display at the Tower of London, England.

Image taken from W.W. Greener's The Gun and its Development, Second Edition. Click on image to enlarge.

The above image shows a round shield with a built in matchlock firearm. These shields date from the 16th century and were ordered by King Henry VIII for use by his bodyguards. About twenty specimens still remain in the present day. The pistol uses a breech-loading mechanism. Also note the grill on the shield. This allows the user to hide behind the shield, but still aim the firearm at the enemy.

The image above is also due to King Henry VIII of England. It is currently on display in the Tower of London as well. This is a combination of a spiked mace with three hidden matchlock pistols in it and is called Henry VIII's Walking Stick. He was known to wield this weapon personally and often took it with him when he would wander about town at night, to check to see if his constables were doing their duty. Unfortunately for him, one of his constables at the parish of St. Magnus (near the London bridge) did his duty very well. He confronted the disguised King at the bridge-foot and demanded to know what this suspicious character was doing with a mace so late in the night. When the King tried to escape, the constable called a watchman to assist him and together, they arrested the King and tossed him into a unlit, cold, tiny prison cell for the night (Such prisons for vagrants, debtors and beggars were called Poultry Compters). In the morning, when his identity became known, the King personally summoned the constable and the watchman who'd arrested him. The two came in trembling, fully expecting to be tortured and beheaded. Instead, they were commended for their honesty and integrity and rewarded with large gifts. The King also immediately passed a law that granted an annual stipend of 23 pounds as well as a large quantity of bread and coal annually for ever to the prison where he spent the night, for the benefit of his fellow prisoners and any other future prisoners! In an article in The London Magazine Vol. III from 1833, it was mentioned that the parish was still receiving its annual grants.

The above image shows a whip which conceals a flintlock pistol within it. The barrel is about 12 inches long and the firing mechanism is concealed by the tassels on the whip. This particular specimen was once the property of a notorious Neapolitan bandit. However, it must be noted that such whip-pistols were not exclusively used by bandits alone. In the 17th and 18th centuries, similar weapons were presented to drivers of French mail coaches travelling south of the town of Lyons.