How did they name cartridges - II

When we left off in our last post, we saw that cartridges like .45-70 and .50-90 were named based on their caliber and the amount of black powder in it (e.g. .45-70 has a bullet of .45 inches in diameter and 70 grains of black powder). We also saw that if two different bullet weights were available for the same cartridge, then a 3 number scheme was used (e.g. .45-70-405 and .45-70-500, where the 405 or 500 indicates the weight of the bullet in grains). We will continue our discussion in this post.

With the invention of newer smokeless powders, cartridges still retained the same two digit naming scheme as before: e.g. the famous .30-30 Winchester rifle, .32-20 Winchester or the .30-40 Krag, which replaced the .45-70 in US military service. As before, the first number indicates the caliber (e.g. 0.30 inches diameter) and the second number indicates the amount of smokeless powder in grains.

After some years, people began to drop the amount of grains and use the year that the cartridge was introduced instead. For instance, the Springfield .30-06 cartridge. This cartridge's diameter is 0.30 inches and it was introduced in 1906 (from which we get 06) and therefore it was named as .30-06. The .30-06 actually replaced the .30-03, which was, predictably, adopted in 1903.

Some years after that, people began to drop the second number altogether and simply name the cartridge after the caliber and the company that introduced it  (e.g.) .44 Colt introduced by Colt firearms, .32 S&W invented by Smith and Wesson etc. Sometimes they were named after a specific product (e.g.) .45 ACP where ACP stands for Automatic Colt Pistol. Sometimes they were named after specific attributes (e.g.) .38 Special, .44 Magnum, .577 Express etc., where the words Special, Magnum or Express indicate that these cartridges have extra power.

By the 1950s, people also started to name the first number by the groove diameter of the rifle, rather than the bore diameter of the bullet (at least in America). For instance, .308 Winchester, where the bore diameter is 0.300 inches, but the groove diameter is 0.308 inches.

Over in Europe (except for the UK), people generally use the metric system and name cartridges with two sets of numbers separated by an "x". e.g. 7.62x51, 5.56x45 etc. The first number is the bore diameter of the bullet in millimeters (e.g. 7.62 mm., 5.56 mm. etc.) and the second number is the length of the case in millimeters (e.g. 51 mm., 45 mm. etc.). Note that the first number is the bore diameter, not the groove diameter. Therefore, what we call the .308 Winchester in America actually has a bore diameter of 0.300 inches and a groove diameter of .308 inches and the Europeans take the 0.300 inch measurement and convert that into millimeters (7.62 mm.) and use that in their cartridge nomenclature. This system is generally used in the rest of the world as well (Asia, Africa, South America, Oceania etc.)

The British tend to name their cartridges in American fashion, e.g. .244 H&H Magnum (where H&H stands for Holland and Holland, a famous British firearms firm), .455 Webley (invented by Webley, another British firearms manufacturer) .700 Nitro Express etc. The numbers indicate the diameter of the bullet rather than the groove diameter though.

These are generally the naming schemes in vogue these days, but there are exceptions to the rule. American manufacturers in particular, tend to add names that sound good to consumer ears: e.g. .22 Hornet, .221 Fireball, .224 Rocket etc. Also, there are cartridges such as the .280 Remington (which actually has a bore diameter of 0.277 inches and groove diameter of 0.284 inches) and the .260 Remington (which actually has a bore diameter of 0.256 inches and groove diameter of 0.264 inches). Remington's marketing people decided that customers like numbers that end in zero better, so they named then .280 and .260 instead.

As you can see, these are several ways how cartridges have been named throughout history.

How did they name cartridges - I

In the world of firearms history, we often see famous cartridge names like .30-30 Winchester, .45 ACP, .30-06 Springfield etc. So how exactly do cartridges get named and is there some meaning behind their naming convention. We will study those in this post.

Bear in mind that cartridges are not always referred by the same name throughout history. For example, when Smith & Wesson produced their first revolver model, they made it fire a .22 cartridge, which was then referred to as a ".22" or a ".22 caliber" in 1857, since there were no other cartridges with the same caliber bullet. This cartridge contained 4 grains of black powder in it and a bullet weighing 29 grains (or 2 grams in the metric system) and measuring .222 inches in diameter. In 1871, Smith & Wesson produced another cartridge in .22 caliber diameter. This cartridge used the same 29 grain bullet as its predecessor, but the case was a bit longer than the older one and contained more black powder (5 grains), in order to produce extra power. Therefore, they began to refer to the old .22 cartridge as ".22 Short" and the new one as ".22 Long". Both these cartridges were used for revolvers. Soon afterwards, Remington, Stevens, Winchester etc. started producing the ".22 Extra Long" for rifles and revolvers. This cartridge used a 40 grain (3 gm.) bullet and a longer case that contained 6 grains of black powder in it. Then, the Stevens Arms and Tool Company combined the case of the .22 Long with the 40 grain bullet of the .22 Extra Long to produce the ".22 Long Rifle" (a.k.a. ".22 LR" cartridge).

Public domain image of different .22 caliber cartridges.

The .22 LR became very successful and still remains the most popular cartridge in the present day. Therefore when someone talks about ".22 caliber" in today's world, they are almost certainly referring to the .22 LR cartridge. However, back between 1857 and 1871, when someone said ".22 caliber" they would have been referring to what we now call ".22 short". So you can see how common cartridge designations have changed over the years.

For some early cartridges, they were named with two sets of numbers. For instance, right after the US Civil War, the US government issued the ".50-70 Government" cartridge for use with the Springfield Model 1866 rifle. This was later replaced by the ".45-70 Government" cartridge in 1873. So what do the numbers .50-70 and .45-70 mean? For a ".50-70", it means that the cartridge has a .50 caliber bullet and 70 grains of black powder. Similarly, a ".45-70" has a .45 caliber bullet and 70 grains of black powder. This naming scheme was also used for other cartridges such as the ".50-90 Sharps", ".50-100 Sharps", ".50-110 Winchester" etc.

In some situations, these cartridges were also referred to with three sets of numbers, such as ".50-70-450" and ".45-70-405" where the third number indicated the weight of the bullet in grains. This was done as cartridges of the same size, but with different bullet weights, became common. For instance,  the .45-70 cartridge case was used for two different bullet weights and to tell them apart, the two cartridges were called .45-70-405 and .45-70-500, when the 500-grain-bullet variant was invented in 1884.

In the next section, we will look more into the conventions used to name cartridges.

What is +P and +P+ Ammunition?

In the world of firearms, some of you readers may have heard about the terms +P and +P+ (pronounced as "Plus-P" and "Plus-P-Plus"). So what is this all about anyway?

In the US, several firearms and ammunition manufacturers jointly formed a standards body called SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) at the behest of the US government in 1926. This organization was charged with setting standards for the firearms industry and contributes its specifications and documentation to the American National Standards Institute (ANSI). All major manufacturers of firearms and ammunition in America are members of the SAAMI association, as are many of the smaller manufacturers. While the SAAMI association requires its members to follow the standards and guidelines that it sets, the US government does NOT enforce the SAAMI standards by law (unlike the European CIP standards, which are a compulsory standard enforced by law in several European countries). It is also not required for a manufacturer to be a member of the SAAMI association either (and some smaller ammunition manufacturers are not and therefore not required to follow SAAMI standards). These two facts are important as we will soon see.

One of the SAAMI association's jobs is to define the maximum pressure allowed to be generated by various cartridge calibers. Some of those standards were defined a long time ago (e.g. 9 mm. Luger, .45 Colt, .38 Special etc.) and it became clear that many modern firearms could easily withstand higher pressures than what the SAAMI standards said, because of improvements in metallurgy techniques. Some law enforcement departments began to clamor for more powerful cartridges to increase the effectiveness of their handguns and some manufacturers began to manufacture +P cartridges, with the +P to indicate that the cartridge was loaded to generate higher pressures than the SAAMI standard. The +P sign would be stamped on the cartridge box and on the base of the cartridge as well.

A 9mm. Luger +P cartridge on the left and a regular 9 mm. Luger cartridge on the right. Note the letters "+P" stamped on the left.

Soon, SAAMI got into the act and established an official +P standard for a few common cartridge types. Typically +P ammunition generates about 10% more pressure than the non +P type, though this is not true for all cartridge types. For instance, plain 9 mm. Luger ammunition is supposed to generate a maximum pressure of 35000 PSI (Pounds per Square Inch), but 9 mm. +P Luger ammunition can generate a maximum pressure of 38500 PSI per the SAAMI standards. The idea behind the +P standards is that older firearms can use the regular ammunition and newer firearms which are built to higher standards may be able to use both regular and +P ammunition safely. While there are SAAMI standards in place for +P ammunition for some calibers (SAAMI only specified them for 5 cartridges types), there are manufacturers that make "+P ammunition" for other calibers as well. Since the SAAMI standards are not enforced by law, manufacturers can mark any ammunition as +P even if SAAMI doesn't have a standard for it. This is even more so for manufacturers who are not members of the SAAMI association.

Soon, some ammunition manufacturers (such as Federal, Winchester and Remington) started making even more powerful ammunition than +P and called these as "+P+". These were meant to be sold to law enforcement officials only, but this is not always enforced. Some think that this was merely a marketing tactic to make it appear as though non-law-enforcement buyers were getting something really special and forbidden.

+P+ ammunition standards are not defined by SAAMI, but general industry agreement is that it should be about 10-15% more powerful than +P ammunition. For example, 9 mm. +P+ Luger ammunition generates a maximum pressure of about 42,000 PSI.

Using overpressured ammunition increases the wear and tear of firearms. While more modern firearms can handle higher pressures, older firearms cannot handle +P and +P+ ammunition that well and may have safety issues. That is why it is advisable to check the user manual to see if +P and +P+ ammunition can be used with a particular handgun model or not.

Why does a M16 have Tall Sights?

When we look at an M16 rifle (or its semi-automatic only civilian cousin, the AR-15), there is something noticeable about their sights:

A M16A2 and two M16A4s. Click on images to enlarge. Public domain images.

In all these examples, note that the sights are a good 2.5 inches from the top of the barrel. Why is this the case with the M16 family? We will study the reason in this post.

The first thing to notice in the M16 family of firearms is that the stock is in line with the center of the barrel. In most other rifles, the stock is a little below the line of the barrel and they have small sights mounted on top:

Click on images to enlarge. Public domain images.

The reason why the stock is below the barrel is for ergonomics. When the user rests his/her cheek on the comb of the stock. the user's eye is aligned just above the top of the barrel and therefore the sights can be placed right above the top of the barrel for such firearms.

However, for such stocks, when a bullet is fired, the recoil pushes back in the line of the barrel and the resistance offered by the user's shoulder is below the line of the barrel and this creates a rotational torque. We studied this effect when reading up on muzzle brakes and compensators earlier:

Here, A is the force acting because of the recoil and B is the force resisting the movement from the user's hand and shoulder on the grip and stock. Since A is higher than B, this causes the rotational torque C, which causes the front of the barrel to rise when shooting. This can cause a loss in accuracy, especially when firing rapidly.

In the M16 family of rifles, the rotational torque is minimized by placing the stock higher, so that forces A and B are around the same line with each other. This is called a "straight line layout" and is done in order to make the rifle easier to control, especially when firing in burst fire or automatic fire modes. One more nice feature of the straight line layout is that it allows the operating rod and buffer to run directly back into the stock and thus reduces the overall length of the rifle. However, with a straight line layout, the user cannot comfortably aim the rifle if the sights are just above the line of the barrel. Hence, the solution was to make the sights taller on the M16 family, so that the user can place their cheek on  the stock and still look through the sights comfortably.

By the way, the M16 isn't the only rifle that does this. The German FG42 and MG42 and the US M60 are three earlier examples that have tall sights as well:

FG42 and M60 machine guns. Click on images to enlarge. Public domain images.

In the above images, note that they all have a straight line layout. The FG42 was one of the first firearms to have this feature and came out during World War II. The straight line layout was later adopted by others, such as the M16 family, the Russian Dragunov rifle, the German Heckler and Koch HK36 and XM8, the Swiss SIG SG 510 etc.

A Swiss SIG SG 510. Click on image to enlarge. 

Licensed by user Rama under the Creative Commons Attribution-Share Alike 2.0 France license from wikipedia.org

With taller sights, the user can rest his/her cheek on the comb of the stock as usual and still aim comfortably through the sights. This is why all rifles with straight line layouts have taller sights.

Unusual Firearms: The Gast Gun

During World War I, aerial combat between aircraft happened for the first time in history. It soon became apparent that machine guns were needed on aircraft, because pilots needed to get a large number of rounds on target to score a kill. However, the high rates of fire were also the cause of certain problems. For one, the frequency of jamming increased with the firing rate. Another problem was how to provide adequate cooling for the barrel after firing a large number of bullets. The gun we will study today attempted to solve these problems in an unusual way.

The Gast gun was invented by Karl Gast, a German, during January 1916. He was working for the Vorwerk Company at this time. Karl Gast's solution to the heating and jamming issues was, rather than using one gun, his idea was to combine two barrels and two actions into a single firearm. What was unique about this mechanism was that upon firing one barrel, the recoil was used to load and charge the second barrel. When the second barrel was fired, the recoil would be used to load and charge the first barrel and so on. Each barrel and action were fed by a separate drum magazine.

Side view of a Gast Machine Gun. Click on image to enlarge.

Gast gun seen from the top. Click on image to enlarge.

Each of these drums held 180 rounds of 7.92x57 mm. Mauser rifle cartridges (also known as 8 mm. Mauser -- it is still a popular hunting cartridge even in the 21st century). Because each barrel would fire alternately, this could easily achieve firing rates of 1600 rounds per minute without overheating or jamming issues. The firearm was also designed for ease of maintenance and could be field stripped in about one minute. Even if there were problems with one side of the weapon, it could still fire single shots from the other barrel. It was also easy to change the ammunition drums and an experienced operator could do this within a few seconds.

Karl Gast first demonstrated this weapon to the German military in August 1917 and they were highly impressed by its design and immediately ordered 3000 guns, with the first 100 guns to be delivered by 1st June 1918. They later changed their minds and ordered 6000 more guns by September 1918.

Plans were also made to manufacture a variant that fired 13x92 mm. TuF ammunition with curved box magazines.

Click on image to enlarge.

However, this variation of the Gast gun never reached the production stage. 

While the gun was very successful, it wasn't very widely used and therefore, the Allies had no idea that it even existed by the time World War I ended. They only found out about it in 1921. Incidentally, Karl Gast had also applied for a US patent in 1920 and finally received it in 1923. The US Army got interested in the design and evaluated one. They found it very reliable, but felt that it didn't offer enough of an advantage over their existing machine guns to justify purchasing it.

The Gast gun was not used by the Germans during World War II, but this didn't mean the end of that design. The Soviets borrowed the concept to design their twin-barreled 23 mm. GSh-23 and 30 mm. GSh-30-2 series of autocannons, used on many of their aircraft in the 1960s and 1970s, such as the MiG-21, MiG-23, Sukhoi Su-25, Tupolev Tu-22 and Tu-95, Mi-24 and Mi-35 helicopters etc. A GSh-23 variant is being used in India's new HAL Tejas fighter aircraft in the 21st century, so this innovative design lives on.

Powder Flasks

In our previous post about powder horns, we noted that these were containers used to carry black powder. As we noted previously, powder horns are actually made out of animal horns (usually cattle, bison or deer). There are containers made of other materials too, which are called powder flasks. We will study them in this post.

We actually saw one example of a powder flask in our last post:

Indian made Powder Flask. Click on image to enlarge. Public domain image.

The above flask is from India and is made of ivory, with some brass and amber fittings. This flask dates to India's Mughal period. These flasks tended to have fine carvings of animals and hunting scenes, such as the two examples below:

Click on images to enlarge, Public domain images.

The above images show two more Indian powder flasks, made of ivory with brass and amber fittings. Pressing on the brass handle opens the mouth of the carved animal figure and dispenses some powder.

In Europe and America, powder flasks tended to be made of copper, tin or brass, such as the examples below:

Flasks made of brass, tin and copper. Click on images to enlarge

As can be seen by the images above, such flasks were commonly decorated with carved hunting scenes or pretty patterns. Some powder flasks were even made of lacquered wood, coconut shells, bone, leather etc.

Powder Horns

During the early part of firearms history, people were forced to carry separate containers of black powder, bullets and wads, because the self-contained cartridge had not yet been invented. Today, we will study one of the early devices that people used to carry black powder around, the Powder Horn.

Black powder has the property that when it is dry, it stays in powder form and can be poured out easily. If it gets damp, then it forms cakes and wetness also prevents it from burning at all. Hence we have the American saying, "keep your powder dry", which means "be prepared for action". This saying allegedly originated in England with Oliver Cromwell, who allegedly said "Trust in God and keep your powder dry". Whatever the origin, there was a need for firearm users to keep their powder dry and this is why powder horns were invented.

The use of animal horns to carry black powder was mainly due to a few reasons:

1. Animal horns are naturally waterproof.
2. Animal horns are naturally hollow inside.
3. Animal horns are durable and cheaply available (especially cattle and buffalo horn).
4. Animal horns are non-sparking, unlike iron containers which have the risk of creating a spark when two metal parts strike each other.

Powder Horns. Click on image to enlarge. Public domain image.

The powder horn simply consists of a cattle or buffalo horn with wooden plugs on both ends. The horn is hollow and filled with black powder. To dispense some powder, the user merely removes the plug on the narrow end and pours some powder out into a measuring flask. The horn usually has a rope attached to it so that it may be hung from the user's waist. In some cases, the user would decorate their powder horns with attractive artwork (such as the topmost powder horn in the image above).

Cattle and buffalo horns were used to make powder horns, because they were cheap and readily available. However, these were not the only materials used to make powder horns.

Indian made powder horn. Click on image to enlarge. Public domain image.

In the above image, we see a fine powder horn from Northern India dating back to the 17th century Mughal period. It has high quality carvings depicting various animals on its outside surface. This should strictly not be called a "powder horn", since the material used is not a horn at all. Strictly speaking, this is a powder flask, which we will study about more in the next post. The above container is actually made from elephant ivory, with some amber and brass parts. When the brass spanner handle is depressed, it opens the mouth of the antelope at the end and dispenses powder. The brass spanner also has a loop so that the hunter can easily carry this on his belt.

Once the cartridge was invented, people did not need to carry powder horns any more, as it was more convenient to carry cartridges which already had the powder pre-measured, along with a ball wrapped in it. Hence, the use of powder horns started to decline during the 18th century. These days, the only users of powder horns are history enthusiasts who like to hunt the way that their ancestors did.