Detailed analysis of the Belgian FN EVOLYS light machine gun
On May 6, 2021, the Herstal National Arsenal (FN) in Liege, a century-old factory, launched its own brand new Product --- EVOLYS (evolution) light machine gun. This light machine gun still uses the most common bullpup structure and the short-stroke piston principle that is rare on machine guns. The bolt is locked in reverse and is ready to fire; the handguard is a receiver-casing integrated design similar to SCAR, and the traditional right-side throw The shell and the magazine chain are hung directly under the gun body; it has two shooting positions: fully active and semi-active. The rear end of the receiver uses a SCAR-like "snow boot" butt.
EVOLYS now has 2 models. The theoretical rate of fire is a moderate 750 rounds per minute. They fire two NATO standard bullets, 5.56 mm and 7.62 mm respectively. The maximum overall lengths are 850 mm and 1025 mm respectively ( The stock is 850 mm and 925 mm respectively), the barrel length is 14 inches (355 mm) and 16 inches (406.4 mm) respectively, and the weight is 5.5 kg and 6 kg respectively. Compared with the US military's M249, this 5.56mm version of the light machine gun is very light, with an empty gun weight of only 5.5 kilograms, while the M249 reaches 7.5 kilograms.
Overall, the layout of the EVOLYS light machine gun is closer to the design style of a rifle. Through FN’s publicity, we can learn that this machine gun is characterized by its light weight, first-class feel at the center of gravity, rich guide rail interfaces, easy operation by both left and right hands, and the ability to install a matching silencer for shooting.
Leather rails are added to the top of the gun and below the handguard. A scope can be added to the top, and a small grip can be added to the bottom. This is actually a necessity for light machine guns nowadays. After all, you advertised earlier that it can be operated like a rifle, so when you hold it and shoot, it must be more comfortable to have a vertical grip. Needless to say, there is no need to mention the scope. With such a short barrel, a scope is needed for long distances.
The front end of the barrel of the EVOLYS light machine gun uses a three-pronged flash suppressor. Since the barrels of the two models of EVOLYS light machine guns are not long, a three-pronged flash suppressor is selected that is easy to hook but has better flame suppression effect. Type flame arrester is reasonable. The flame arrester can be easily installed with a silencer, and the gas guide hoop is also equipped with a "gas conditioner". However, this "gas regulator" does not have the function of adjusting the air conduction volume. It is a cover designed to facilitate the removal and cleaning of the piston.
The most unique thing is the ammunition supply system of the EVOLYS light machine gun. Its ammunition chain is inserted diagonally from the lower left to the right. It is very different from ordinary machine guns. Only the bomb receiver cover is horizontal. Open and close. The oblique ammunition supply system has three advantages:
First, it reduces the exposed part of the ammunition chain. The bullet receivers of traditional machine guns are all at the top. After pulling out the bullet chain from the bullet chain box under the gun body, not only does the bullet chain have to make a right-angled bend before loading, but a certain part of the bullet chain is still exposed. If there are foreign objects on the ammunition chain, they will be sent into the firearm by the ammunition supply organization, which will have a certain impact on reliability. The oblique ammunition supply system of EVOLYS is very close to the magazine, which alleviates the above problems.
Secondly, the side-mounted receiver seat will not damage the top structure of the receiver. A long and continuous Picatinny rail can be installed on the top of the EVOLYS receiver. The opening and closing of the receiver cover will not only not block the sight of sight, but can even be equipped with a tandem sight like a rifle. Furthermore, one-handed filling is relatively convenient. When loading the ammunition chain, the right hand does not need to leave the grip, and only a small amount of operation is required with the left hand.
This gun also has a patent, called the horizontal ammunition supply mechanism, which can replace the ammunition chain with one hand. During the replacement of the ammunition chain, if the ammunition chain is not installed in place, when closing the receiver cover, you can Actively reset the bullet chain, and after firing the last bullet, the bullet chain of the last bullet can be automatically dropped out to speed up the reloading speed. Generally, the bullet chain can be shot. After the last round is fired, the bullet chain will stay in the gun and will not fall out by itself. The shooter needs to remove it. FN is said to have solved this problem.
Why does EVOLYS use a short piston gas guide instead of the long piston gas guide commonly used in general machine guns. First of all, it must not be for accuracy. Because if you look carefully, you can find that the piston and the front extension of the bolt frame are coaxial, and the height of the piston axis has not been reduced at all. Moreover, as a machine gun, the main motor is also heavy, so it is unlikely that a short piston gas guide was used to improve accuracy.
The author believes that the reason why the EVOLYS light machine gun uses a short piston gas guide is mainly to use a silencer. If a long piston gas guide is used, the gunpowder gas may flow along the piston barrel and bypass the piston directly into the receiver. This will be more obvious when a silencer is installed and the muzzle resistance increases. FN stated in the promotion that even if EVOLYS is equipped with a silencer, there will not be too much dirt that affects the shooter's shooting experience. The short piston air guide may have a certain effect.
The EVOLYS light machine gun has unlimited potential. This does not mean that its design is very good or its performance is excellent, but that its layout is groundbreaking for light machine guns. The words suppressor, tandem sights, and excellent center of gravity have long been used to describe rifles. FN applies the development of rifles to almost stagnant machine guns, striving to make the light machine gun ensure the continuity of firepower and burst accuracy while improving the hand feeling, ergonomics and expansibility, and even meet the needs of special operations to reach the level of rifles. flexibility.
Now, the EVOLYS light machine gun has been officially unveiled at the World Defense and Security Equipment Expo in London, and was also vigorously promoted by FN at the Dutch Army's "Urban Environment Combat" theme day. This light machine gun may be hampered by immature planning now, but if it can be continuously improved, I believe it can indeed take on the responsibility of evolving the light machine gun.