Chain Guns - II

In our last post, we studied chain guns from the 19th century. In today's post, we will study modern chain guns.

When we look at firearms throughout history, repeating firearms have been based on two different feed mechanisms:

• In the first category, we have manually powered feed mechanisms (i.e.) the firearm is loaded and cocked by the user pulling a lever somewhere on the firearm. In this category, we have mechanisms like bolt action, lever action, pump action etc., as well as revolver mechanisms such as single action revolver, double action revolver etc. Firearms in this category have a firing rate based on how fast a human can manipulate the reloading mechanism and then pull the trigger. In some cases (e.g. double action revolvers), the act of pulling the trigger drives the feed mechanism and also fires the firearm. The firearms in this category are generally older and date from 18th and middle 19th century.
• In the second category, we have firearms that use some of the energy from firing a cartridge to drive the feed and firing mechanism. In this category, we have semi-automatic and fully automatic firearms of various types, such as blowback operated, recoil operated, gas operated etc. Firearms in this category are generally from the late 19th, 20th and 21st century and include most modern pistols and rifles. The reloading/feed mechanism operates faster than what a user can accomplish manually and therefore, these firearms have a faster firing rate than firearms in the first category. 

Firearms in the second category are very common in the 20th and 21st centuries. However, they generally have one weakness -- if a cartridge is faulty and does not fire properly, then the feed mechanism stops working and the user has to stop shooting until the faulty cartridge is removed. Firearms in the first category don't have this problem -- if a cartridge is bad, the user can usually pull the feed lever again and use the next cartridge in the magazine.

Since the latter part of the 20th century, we can add a third category for repeating firearms: using an externally powered source to drive the feed mechanism. In this category, we have modern chain guns. A chain gun uses an electric motor and a continuous chain to drive the feed and firing mechanisms. The chain is similar to that used in bicycles and motorcycles. Unlike weapons in the second category, a faulty cartridge will not stop the weapon from operating, since the mechanism is driven by external forces and the faulty cartridge will be merely ejected out.

It might be interesting to note that while there are quite a few chain driven guns made by different companies, the words "Chain Gun" are actually a registered trademark owned by Alliant Techsystems Inc. 

Hughes EX-34 Chain gun. Click on the image to enlarge.

The above image shows a Hughes EX-34 chain gun and guns based on its operating system are found on helicopters, tanks, armored fighting vehicles etc.

Schematic of the Hughes chain drive system. Click on the image to enlarge.

The above image is from a patent document that shows the mechanism for the Hughes chain driven gun. The chain is powered by an electric motor that runs on 24 to 28 volts. The chain operates the ammunition belt feed, as well as powering the extraction mechanism and the firing mechanism. 

MK 38 Machine gun. Public domain image.

The above picture shows the MK 38 machine gun system, which is used on US Navy ships since 1986. It has a range of 2700 meters, fires 25 mm. (1 inch) shells and is used as a defensive weapon to counter fast moving surface targets.

In chain driven weapons, the rate of fire can be adjusted as needed and most chain driven weapons have multiple firing speeds. For instance, the Bushmaster M242 can be fired in single shot, burst and fully automatic modes. 

Chain driven mechanisms are generally used for larger caliber guns and auto-cannons and have a correspondingly bigger recoil than hand held firearms. Therefore, most chain guns are usually mounted on a vehicle, such as a ship, helicopter, tank etc.

Chain Guns - I

The previous article on the topic of ammunition belts prompted a vague recollection in your humble editor's mind of another feeding mechanism: chain guns. We will study them in today's post.

A chain gun uses a continuous chain that is driven around a couple of sprockets, to feed the firearm. The chain has chambers where cartridges may be loaded. Many designs using this concept were developed from around 1850-1880 or so. One of the early models was the Treeby Chain gun invented in 1854.

The Treeby Chain Gun, courtesy the Forgotten Weapons Blog. Click on the images to enlarge.

The above images are from the Forgotten Weapons Blog, a wonderful source of information. This weapon is somewhat complex to operate: the user has to rotate the lever on the barrel upwards, which pulls the barrel away from the chamber. Next, the hammer is cocked, which also rotates the chain and brings the next cartridge into the chamber. Then the user rotates the lever back down, which pushes the barrel back against the chamber, thereby sealing it. Now the gun is ready to fire. However, the gun was rejected by the British military for various reasons, one of them being that if the user didn't lock the barrel back before pulling the trigger, bad things could happen. Only two prototypes of this gun were known to have been built.

Over in America, the Josselyn Revolver was patented in 1866 by Henry S. Josselyn.

Public domain image of the Josselyn revolver patent. Click on the image to enlarge.

The details of Henry Josselyn's patent may be found here. A specimen of this revolver is in the Smithsonian museum. Like the Treeby chain gun, the Josselyn revolver didn't sell as well either, possibly because of the inconvenience of carrying one around.

Finally, in 1878, a French civil engineer named Paulin Gay and a French merchant named Henry Guenot patented chain driven firearms, the Guycot pistol and Guycot rifle.

A Guycot pistol. Click on the image to enlarge

A Guycot rifle. Click on the images to enlarge.

The Guycot guns have a chain with cups that can hold centerfire cartridges. The chain is looped through the receiver and the stock. Pulling the trigger revolves the chain and also retracts a firing pin backwards and then releases it to strike the cartridge and fire it. This means that once it is loaded, the gun can be fired as fast as the user can pull the trigger. Paulin Gay reportedly got the idea of using a chain in 1882, after observing chains being used to cut stone blocks in a quarry. Shortly after receiving their French patent in 1878, the inventors also received a British patent in 1879.

The Guycot pistol has a capacity of 40 cartridges and the Guycot rifle can hold 80 cartridges. Compared to their competitors during that era, the Colt revolver (holds 6 cartridges) and the Henry rifle (which can only hold 16 cartridges), the Guycot pistol and rifle have a huge advantage in capacity. However, they never really caught on for some reason either.

There were also other similar chain gun patents from that era.

Mechanism of a "Bicycle chain" gun from a 19th century patent. Click on the image to enlarge. Public domain image.

The above image is from a 19th century patent for a handgun.

In spite of having larger capacities than other firearm types of that era, chain guns didn't sell very well as personal defense weapons because of the inconvenience of the loose belt hanging out of the firearm. However, they are well suited for machine guns, which hadn't been invented yet. In our next post, we will look at some modern chain guns.