Friday, December 27, 2013

Is it a shotgun or a rifle? The Paradox gun

In the 19th century, the British Empire spanned a large portion of the globe. This was a time when rich English sportsmen would undertake expeditions to remote parts of the world to hunt exotic birds and animals. To hunt small targets that could be approached at closer ranges (e.g. birds, rabbits etc.), the best weapon that hunters could use were shotguns and to hunt larger furry animals that needed to be shot at longer ranges (e.g. deer, buffalo, tigers etc.), hunters would use rifles.

However, this meant that sportsmen would need to carry two different kinds of firearms for their expeditions: shotguns and rifles. Bear in mind that rapid reloading technologies were not yet fully developed at that time and the standard method of hunting in these expeditions was for the hunter to carry one loaded firearm and have a few assistants (called "gun bearers") standing next to him, each carrying another loaded firearm or two. After the hunter had fired his weapon, one assistant would exchange his loaded firearm with the hunter, so that the hunter could continue firing at targets, while the assistant reloaded the other firearm. Also, because there was a chance of parts breaking in the field, a hunter would typically pack several rifles and shotguns for an expedition, so that he would not have to return early, if one firearm broke.

Sportsmen of that era, expected to hunt both birds and animals on a long expedition and hence, they would pack both shotguns and rifles for their journeys. This made their baggage heavier, since these are two different firearm types. This was the situation until 1885, when a British colonel named George Vincent Fosbery, invented a firearm that could be used as both a shotgun and a rifle. His invention consisted of a large shotgun with a mostly smooth barrel, but the last few inches of the barrel near the muzzle were rifled with a special "ratchet" style. The famous British firearm manufacturer, Holland & Holland, immediately bought the patent rights for this firearm and began to market it as the Paradox gun in 1886.

Patent document from 1885 showing the design of the Paradox gun's special barrel.
Click on image to enlarge. Public domain image.

Muzzle of a 12 bore Paradox gun showing the special rifling.
Click on image to enlarge. Image licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license by user "Lord Mountbatten" at wikipedia.

19th century advertisement for the Paradox Gun. 
Click on image to enlarge. Public domain image.

The word "paradox" means a statement that apparently contradicts itself. The reason that Holland & Holland chose to market this firearm with this name was because the defining nature of a shotgun of that era was its smooth barrel, but this was a shotgun with rifling in the barrel, hence it was a paradox!

The hunter could now carry one gun and two different types of cartridges and load the appropriate cartridge type, depending upon the target. Holland & Holland built about 1500 Paradox guns of various sizes between 1886 and 1930. They were built for a variety of bores: 8, 10, 12, 16 and 20 gauge.

While Holland & Holland owned the trademark "Paradox gun", they were not the only manufacturer of this type of dual-use firearm. Other British manufacturers made them for sale under their own names or for other companies to sell under their brand names (e.g.) Westley Richards and G & S Holloway. Westley Richards started manufacturing these guns in 1905 and sold them under the trademarks "Explora" (for larger bore 12-gauge gun models) and "Fauneta" (for smaller bore 20 and 28 gauge gun models). Some of G & S Holloway's products were resold in India by P. Orr & Sons, a high end jeweler and watch dealer in Madras (now Chennai), India, so their products are marked with both G&S Holloway and P. Orr markings. Some of these firearms occasionally show up in firearm auctions. P. Orr & Sons are still in business, although they have stopped selling firearms since around 1970 and only sell clocks and watches now.

Vintage advertisement by Westley Richards for their Explora model gun. Click on image to enlarge

In 2006, Holland & Holland announced that they would start manufacturing Paradox guns again, after a break of over 70 years and they are currently selling new models.

Friday, December 13, 2013

The M1895 Nagant Revolver

In our last post, we talked about the concept of "cylinder gap". Briefly, revolvers have a gap between the cylinder and the rear of the barrel, in order to allow the cylinder to rotate freely. However, when a revolver is fired, some of the hot gases will escape through this gap, possibly flushing some metal particles as well, which is why it is dangerous to have body parts close to the front of the cylinder. We discussed all of this in our last post (please read it, if you haven't already done so). We also pointed out that due to some of the gases leaking out of the cylinder gap, this decreases the velocity of the bullet coming out of the revolver. In today's post, we will look at a revolver that attempted to solve this problem. We are talking about the Nagant M1895 revolver, which will be the subject of today's post.

The Nagant M1895 was a revolver designed in 1895 by Leon Nagant, for the Russian empire. The Nagant Brothers company was Belgian, but they were well known to the Russian military, because they were involved in an earlier competition to design a new rifle for the Russian military previously (the result of the earlier competition was the Mosin-Nagant M1891 rifle, although Nagant's contributions to the final design was very minimal).

The Nagant revolver design attempted to minimize the velocity loss, by making the revolver gas-tight as possible. We will discuss how this was achieved here.

Mosin-Nagant M1895 Pistol. Click on image to enlarge.
Image licensed under Creative Commons Attribution-Share Alike 3.0 Luxembourg license by user Mascemon @ wikipedia

At first glance, the revolver appears to have a pretty large cylinder gap, as can be seen by the image above. However, the revolver is built with a special mechanism, so that when the hammer is cocked, the cylinder not only rotates to the next chamber (just as any other revolver), but it is also pushed forwards toward the barrel, thereby closing the cylinder gap and creating a seal with the forcing cone at the back of the barrel.

Now, the cylinder is just one part of the gas-tight seal. Let's take a look at the unusual cartridge for this revolver. Here's a closer look at it:

From left to right, Nagant 7.62 mm., .32 S&W Long and .22 Long Rifle (.22 LR) cartridges.
Picture courtesy of Commander Zulu at Wikipedia.

The cartridge on the left is the one for the Nagant revolver. Compared to the other two cartridges, a few differences are clearly visible. Unlike the other cartridges, the Nagant cartridge fully encloses the bullet inside the cartridge case. Note that the neck case of the cartridge is crimped to a smaller diameter and the bullet does not protrude out of the end. This is part of the design. When the cylinder is moved forward into the forcing cone, the cartridge's unusual neck is forced between any gap left between the cylinder and the forcing cone. When fired, the neck expands into the forcing cone and fills any remaining gaps, making it even more gas tight. As a result of this, the Nagant M1895 does not leak much gas through the cylinder gap when it is fired, and the bullet comes out about 50-150 feet/sec (15-45 meters/sec) faster when it is fired.

As we saw in an earlier post, temperature has an effect on ammunition performance. By making the gas seal tight as possible, this revolver could perform better than other models, even in the middle of very cold Russian winters and with the types of propellants that were available in 1895. A couple of other side-effects are a result of this gas seal design as well. For one, it reduces the chances of injury to body parts in front of the cylinder, because the hot gases and particles don't come out of the side as much. Also because of the gas seal, the noise generated comes out of the barrel, which means that unlike other revolver models, this one can be fitted with a suppressor to reduce the noise.

The video above shows the unusual mechanism and cartridges in very good detail.

This revolver was used a lot by the Russian Empire and then, the Soviet Union, and is used even today by present-day Russian police, despite being out of production for about 60 years. It is regarded very highly in Russia for its toughness.

However, there are a few disadvantages of this revolver as well. The first is that it is much slower to load this revolver than other models. Because of its design, the cylinder cannot flip out of the side to load the cartridges simultaneously. Instead, the user must load and unload each chamber one at a time, via a loading gate on the side. Also, this ammunition does not have great stopping power compared to more modern cartridges. At one time, it was difficult for American users to purchase ammunition for this revolver, even though the revolver is pretty cheap to purchase (typically costs about $100). The trigger is also pretty heavy to use and accuracy suffers as a result.

Before we end this discussion, here's another video done by the same user above (hickok45), demonstrating the effectiveness of the unique gas seal of this weapon.


Tuesday, December 10, 2013

What is a "Cylinder Gap"?

In today's post, we will look into the topic of revolvers and firearms safety and also study the concept of cylinder gaps.

If the reader looks at a revolver, chances are that the reader may observed that, at the area where one of cylinder's chambers aligns with the barrel, there is a small gap between the front of the chamber and the barrel, about the thickness of a business card. This space is called the cylinder gap.

This gap exists in all revolvers, because there needs to be a bit of space between the cylinder and the barrel, in order to allow the cylinder to rotate. In some revolver designs (e.g. the Belgian Nagant 1895 model), this gap is sealed when the weapon is cocked (we will look at this design in a future discussion), but in most revolver designs, this gap is left open at all times.

When a revolver is fired, high pressure gases are generated in the chamber and expand into the barrel, pushing the bullet out. While most of these gases expand into the barrel, a small amount of hot gas comes out of the sides of the cylinder, due to the cylinder gap. If the chamber does not precisely align with the barrel, some metal particles may come out of the side as well. These hot gases and particles come out with a surprising amount of energy, even on a small revolver, and may cause some serious injury. Therefore, it is unwise to place a hand ahead of the cylinder, or even stand close to the side of the person firing the revolver.

Correct ways to hold a revolver

In the above images, we see the correct ways to hold a revolver. Notice that in both cases, the person ensures that the hands are placed well behind the cylinder gap. Now we will look at the incorrect way to hold a revolver.

Incorrect way to hold a revolver. Never do this!

In the above image, we see an incorrect way to hold the revolver. Notice that the user has some fingers placed in front of the cylinder. This is a very bad idea and could result in serious injury, if the revolver is fired. People who are new to revolvers may accidentally do this, because they find it easier to support a heavy revolver, or because they see people doing it with pistols, and they cause injury to themselves.

The above video demonstrates pretty well, how much gas can come out of the sides of the cylinder and why it is a bad idea to put any body parts close to the cylinder gap. In fact, people standing close to the sides of the revolver may feel the hot gases as well, which is why it is best to stand behind the shooter, or some distance away to the side.

The reader may wonder, why is it that gases don't come out of the back of the cylinder? Well, that is because when the revolver is fired, the heat of the explosion causes the sides and back of the cartridge to expand slightly and the rim seals off the back of the cylinder and prevents most of the gas from leaking out of the back.

Due to the leakage of gases through the cylinder gap, the velocity of the bullet coming out of the revolver is slightly reduced. There are designs that attempt to close this gap when firing, so that the entire energy of the expanding gases acts upon the bullet. We will study these designs in a future post.