The M16 Family III - The Clones

A couple of posts ago, we looked at various members of the M16 family. All of the models we have looked at so far, have been developed for the needs of the American military. In today's post, we will look at some more members of the M16 family that were developed by other countries.

In 1984, Canada decided to equip their military with a new rifle and wanted to go with the NATO standard cartridge 5.56x45 mm. In order to save development time and money, they decided to purchase the license to manufacture M16s of their own. A little while earlier, the US Marines were working towards improving the M16A1 model to the M16A2. A Canadian military liaison officer was also present while the Marines were working on improvements and he communicated some of these design changes back to Canada. As a result of this, the Canadian C7 rifle was developed with some features of the M16A1 and some of the M16A2. A Canadian company, Diemaco, was put in charge of manufacturing the new rifle.

C7 (top) and C7A1 (bottom) rifles

The C7 rifle has the stronger and longer stock, barrel with 1 turn in 7 inches twist rate, pistol grip and handguards of the M16A2, but retains the older rear sights of the M16A1, as well as the same firing modes of the M16A1 (single shot and fully automatic). One more major difference, which is not obvious, is that the C7 barrel is manufactured by the hammer-forging process.

The C7A1 incorporated some improvements to the C7, the main one being the replacement of the carrying handle, with a rail that allows the user to attach other devices here, such as iron sights or optics. This is similar to the M16A4 model, however the C7A1 preceded the adoption of the Picatinny rail by the US military, therefore the rail on the C7A1 is of slightly different dimensions than the now standard picatinny rails.

The C7 and C7A1 models are now being replaced by the C7A2 model in the Canadian military. The C7A2 has picatinny rails, in order to be standards compatible with all the accessories that are made to fit on a picatinny rail. It also has rails in front to attach laser pointers or lights. Unlike the previous models, it has a telescoping stock. One more major difference is that the C7A2 rifle furniture is green in color, instead of black. Other changes include ambidextrous magazine release and ambidextrous safety selector levers.

The C7A2 model rifle

The C7 family also comes with corresponding carbine variants, the C8, C8A1 and C8A2. The C7 and C8 families are used by the military forces of Canada, Netherlands, Denmark, United Kingdom (Special Forces mostly), Norway (Special Forces), Canadian Police etc. In 2005, Diemaco (the company that made the rifles in Canada) was bought out by Colt and is now known as Colt Canada.

Another manufacturer of M16 clones is Singapore's ST Kinetics, which produces the M16S1 for Singapore's military. The M16S1 is simply a M16A1 made under a license by ST Kinetics.

Another clone of the M16 family is the Chinese made Norinco CQ. Unlike the C7 family, the Norinco CQ is an unlicensed clone of the M16. While it uses the same 5.56x45 mm. cartridges of the M16, the Norinco CQ was never adopted by the Chinese military. However, they make two models for export, one capable of selecting between single shot and fully automatic fire for military sales and a semi-automatic only version for civilian markets.

Public domain image of a Norinco CQ rifle. Click on the image to enlarge.

It is pretty easy to tell a Norinco CQ apart from other members of the M16 family. First, notice the shape of the stock is completely different from the M16A1, M16A2, C7, C7A1 etc. Second, the handguards in front are also differently shaped than the other members of the M16 family. Thirdly, the pistol grip is curved on the Norinco CQ. Fourthly, the front sight on a Norinco CQ is of the hooded sight type, instead of a sight post.

The barrel of a Norinco CQ has a 1 turn in 12 inches twist rate. Because of this twist rate, it will fire the M193 cartridge designed for the M16A1 properly, but cannot accurately fire the NATO standard SS109 or the newer US M855 cartridge beyond about 100 meters or so (because these require a twist rate of 1:7 for stability in the air).

While the military version of the Norinco CQ was never used by the Chinese military, it is used by military forces of some other countries, such as Cambodia, Syria, Libya, Iran (which makes their own copies of the Norinco CQ), Sudan etc.

Actions: Blowback Action: Gas Delayed

In our last few of posts, we've studied the basic principles of a blowback action and the reason why we want to delay the blowback action. In our last couple of posts, we saw that mechanical means can be used to delay the movement of the bolt, as well as a method that uses friction. In this post, we will look at another way to delay the movement of the bolt -- a method that uses some gas from the cartridge to delay opening the bolt, the Gas Delayed Lock.

In a Gas Delayed lock (as opposed to a gas operated weapon), when the cartridge has just been fired, the case of the fired cartridge tries to push the bolt backwards (all blowback pistols have a common property that the bolt is not locked at the moment of firing). However, some of the gas generated by the cartridge is bled off to a separate chamber that contains a piston and a spring. This piston offers extra resistance to the movement of the bolt and does not allow the bolt to move immediately. This allows the bullet to exit through the front of the barrel, taking most of the high pressure gas out of the chamber via the same exit. When the pressure in the chamber drops sufficiently, the bolt is now free to move backwards.

Public domain image. Click on image to enlarge.

In the above example, there is a hollow cylinder under the barrel which has a piston in it. The other end of the piston is attached to the front end of the slide. When the cartridge is fired, the gas pressure acts on the bullet and pushes it out of the barrel. The pressure also acts on the fired cartridge case, which attempts to move backwards and push on the bolt. However, some of the gas in the chamber is siphoned off and enters the cylinder underneath the barrel and pushes upon the piston. Since the other end of piston is attached to the front end of the slide, the slide now has two forces acting upon it: a force acting on the empty cartridge case that is trying to push it to the right, and a force acting on the piston, trying to push the slide to the left. As a result, the slide and the bolt don't move much at all. When the bullet exits the barrel, most of the high pressure gas leaves via that exit and the lower cylinder loses its pressure as well. As a result, the slide and bolt can now move backwards by momentum. This opens the breech and ejects the fired cartridge case.

The first use of this mechanism in a weapon was in the Volksturmgewehr 1-5 ("People's Assault Rifle"), also known as the VG 1-5. It was designed in 1944 by Karl Barnitzke towards the end of World War II, to be used by the Volksturm (a.k.a. "People's Militia"), which was a secondary force consisting of people in Germany between 16 and 60 years old, who were not already serving in the military in World War II. This weapon was designed to be cheap and easy to produce and used some parts in common with the StG 44 assault rifle.

The Barnitzke design was later used in the Swiss W+F 47 prototype pistol, the Steyr GB pistol, the Heckler & Koch P7 pistol and the Norinco M-77B pistol. In the case of the Norinco pistol, the M-77B is a bigger version of the M-77 and uses a bigger round. The gas delayed blowback system allows it to reduce the recoil of the weapon.