9x39mm subsonic rifle ammunition is a product of the Central Institute of Precision Mechanical Engineering of Russia. Accordingly, the institute has the most types of 9mm caliber rifles. The AS micro-acoustic assault rifle, VSS micro-acoustic sniper rifle, and SR-3/SR introduced earlier -3M small assault rifles are the products of this design institute. However, due to the huge advantages of 9x39mm rifle cartridges in short-barreled melee weapons, other Russian light weapons design units have also designed firearms of this caliber, such as the 9A-91 small assault rifle and VSK-94 sniper rifle of the Tula Instrument Design Bureau.
VSK-94 sniper rifle (top) and 9A-91 small assault rifle (bottom)
9A-91 R & D overview
Central Precision Machinery Engineering Research The SR-3 small assault rifle was originally designed as a concealed security weapon for important personnel, but in practice, it was found that the gun was short and capable of strong firepower. The heavy warhead was suitable for enemies wearing body armor or hiding in cars. The flame and noise are also small, which is very suitable for CQB indoor close combat. Therefore, many elite anti-terrorist departments in the Russian Federation are equipped with this weapon. However, the SR-3 is too expensive, and the design emphasizes the short, small and smooth shape. Some details such as the buttstock with a small butt-folding shoulder plate, the gun frame without a protruding handle, and the lack of a scope guide rail. The man-machine function and function of firearms are expanded, so some units hope to develop a small assault rifle with the same caliber of 9x39mm, low cost, mainly CQB close combat, and suitable for multiple tasks.
For this reason, in the early 1990s, the Russian Tula Instrument Design Bureau independently developed a 9x39mm caliber small assault rifle with its own funds. The design goal was to be lighter in weight and warhead than the AKS-74U short assault rifle currently in service at the time. The penetrating power and stopping effect were greater, and finally this small rifle was finalized and mass-produced in 1994, named the 9A-91 small assault rifle, and equipped with the Russian Ministry of Internal Affairs for trial use in the same year.
9A-91 small assault rifle (stock folded)
9A-91 small assault rifle (stock open)
9A- 91 assault rifle structure
9A-91 assault rifle has a compact shape, a total length of 605mm, and a full length of 383mm when the butt is folded. After folding, it is smaller than the AKS-74U short assault rifle, and weighs 1.75 without a magazine. kg, caliber 9mm, firing 9x39mm rifle ammunition, magazine capacity 20 rounds, theoretical rate of fire 600-800 rounds/min. Since the initial stage of development required to reduce the cost as much as possible, the casing and casing cover of the 9A-91 assault rifle are all steel stamping parts, which are convenient to process and low in production cost. The small grip and handguard of the gun are made of plastic, with waffle-like anti-skid patterns on the surface. The cross-section of the handguard was square in the early days, and the size of the handguard was enlarged in the later period. Better grip comfort.
9A-91 A close-up of the casing, with obvious traces of stamping, spot welding, and riveting.
9A-91 punching case
9A-91 produced later replaced the handguard
9A-91 assault The rifle can be single-shot or burst-fired. The earliest-produced batch insurance/single burst selection lever is located on the left side of the receiver. It is an arrow-shaped part. A red dot is for bursts. When erected, it is for insurance. Later, in order to install a side rail on the left side of the receiver to install the scope, move the insurance/single burst selector lever to the right side of the receiver, above the handle. Although the safety of the gun is closer to the grip, the angle of rotation during operation is relatively large, especially for single-shot/burst-shot switching, which needs to be rotated 180°. One-handed operation is difficult and requires the assistance of the other hand.
9A-91’s buttstock is a folding buttstock with stamped steel plate and a П-shaped cross section. When the buttstock is opened, it is fixed by a spring latch. There is a small shoulder plate behind the buttstock, which is L-shaped.When not in use, the entire buttstock is folded upwards and clings to the top of the receiver cover. In order to be able to fire emergency when the butt is folded, a rear sight hole is opened on the butt, which just accommodates the protruding rear sight when folded, without interference. The buttstock of 9A-91 is compact and compact. The disadvantage is that the shape is not good, the size of the shoulder plate is very small, and the shoulder shooting is not comfortable.
Opened butt
When folded, the butt is close to the top of the receiver cover, and the square hole on the butt rod just accommodates the rear sight.
9A-91 uses a steel-stamped 20 rounds magazine for ammunition. The magazine is double-row double-in. There is an observation hole at the lower side of the magazine. The number 2 is written next to it, which means 20 rounds. This hole You can see that the bullet means the magazine is full. There is a steel plate stretched in front of the trigger guard of 9A-91, which is spot welded and assembled in the magazine well under the receiver. The magazine fixing tenon is similar to the AK rifle and is located in front of the trigger guard.
9A-91's magazine socket
Double row and double feed magazine
Automata is the core structure of automatic weapons, 9A-91 assault The rifle adopts the principle of piston long-stroke air-guided type, and the bolt action is rotated and locked. The automatic machine of this gun is very different from the AS, VSS, SR-3/SR-3M of the Central Institute of Precision Mechanical Engineering, and it is much simplified. In some places, traces of the automatic machine of the AK rifle can be seen, but it is different. AK rifle. The head of the gun has four latching shoots arranged in a cross shape (for comparison, the guns of the Institute of Precision Mechanical Engineering have six latching shoots that are radially symmetrical, and the AK rifle has two asymmetric latches, one large and one small. Projecting bamboo shoots), there is a large shell hook at 10 o'clock from the nose position, the structure is very similar to the shell hook of an AK rifle. The guide post of the bolt is mounted on the side of the bolt body, not on the large latching shoot of the AK rifle, which helps to reduce the horizontal size. The guide column matches the curved guide groove on the bolt frame to move the bolt frame back and forth. Turns into a rotating motion of the bolt, realizing opening and closing. From the shape of the bolt guide, the guide groove of the bolt frame and the locking projection, it can be seen that the automatic machine of 9A-91 still has a flat driving design. When the bolt frame moves back, the driving plane on the guide groove is against the gun. The plane of the machine guide post drives the plane forward to avoid wedging. When the head of the bolt enters the barrel section sleeve, the guiding surface on the one side of the locking protrusion contacts the guiding surface in the barrel section sleeve, forcing the bolt to rotate At an angle, the driving plane of the bolt guide post and the guide groove of the bolt frame are staggered with each other, the guide post enters the locking slope part of the guide groove, and the locking slope drives the bolt to continue to rotate until it is locked. Because the head shape of the bolt is simpler than AS, VSS, SR-3/SR-3M, the 9A-91 adopts a rigid shell ejector similar to the AK rifle, which is powerful and reliable.
9A-91 assault rifle's frame, the piston rod part is similar to AK rifle.
9A-91 assault rifle gun head close-up
The state of the automatic machine when it is seated, pay attention to the driving plane indicated by the arrow.
zoomed in. When the gun frame is pushed back into the gun, it is pushed with the plane marked in red, not by the locking slope, so no wedge will occur.
locked state, at this time the bolt guide post has entered the straight part of the guide groove of the bolt frame.
The guide surface on the barrel section is circled by the red circle, which cooperates with the guide surface on the bolt lock protrusion to make the bolt move an angle. The bolt guide post and The driving planes between the guide grooves of the gun frame are separated from each other; the blue circle circles the rigid ejector on the guide rail of the automatic machine. When the gun is retracted, the ejector hits the bottom of the shell from one side and knocks out the shell. Throw the shell window.
9A-91 The drawing machine handle is a follow-up type, fixed on the right side of the gun frame. For easy operation, this drawing machine handle is designed to be folded upward to avoid hooking.
Pulling machine handle folded upward
As for the firing mechanism, AS, VSS, SR-3/SR-3M of the Central Institute of Precision Mechanical Engineering use hammer translational firing, while 9A-91 is relatively traditional and uses hammer rotary firing. The entire firing mechanism can be disassembled as a whole from the receiver. Observing the shape of the parts of the firing mechanism, it can be found that its working principle is similar to the firing mechanism of an AK rifle. The two front and rear barrier irons are used to control the hammer to achieve single shot and continuous shot.
9A-91's hammer revolving firing mechanism
sights, because the 9A-91 barrel is very short, the original purpose of the design is to be used for close combat, so mechanical sights The setting is very simple, there is an L-shaped flip-out ruler with wings behind the handguard, with 100m and 200m gaps, and a front sight with wings above the muzzle. The first 9A-91 produced without a scope interface, and soon a scope guide rail was added to the left side of the receiver, which can install various Russian-made photoelectric scopes.
9A-91's rear sight and front sight
Scope guide rail on the left side of the receiver
equipped with bullets
9A-91 assault rifle can fire a variety of 9x39mm subsonic rifle bullets, but the design of the gun is mainly considered as a CQB melee firearm, not as a professional micro-sound gun (although 9A-91 can also be equipped with a muzzle silencer), No consideration was given to using it as a micro-acoustic sniper rifle, and the existing 9x39mm SP-5 sniper shells and SP-6 armor-piercing shells were more expensive. In the view of the Tula Instrument Design Bureau, if the cost of directly using SP-5 and SP-6 bombs is too high, it may affect the market share of the gun (considering that there was not the worst in Russia in the 1990s, only worse Economic conditions, the federal to local law enforcement agencies are indeed very tight), so they specially developed a cheap 9x39mm rifle bullet-PAB-9 rifle bullet for the 9A-91 assault rifle.
9x39mmPAB-9 bullet (early test type)
PAB-9 rifle bullet’s bullet structure is very similar to the SP-6 armor-piercing bullet of the Central Institute of Precision Mechanical Engineering. It is a semi-armored pointed bullet and runs through the entire The warhead has a thick steel core and the head is exposed. In order to reduce costs, the steel core of the PAB-9 bullet is not polished, but stamped. The quality is rough and the hardness is not as good as the steel core of the SP-6 bullet. The PAB-9 bullet can only be used for 9A-91 assault rifles. It cannot be used for several other 9x39mm caliber weapons. Forced firing will cause excessive wear of the barrel. The only advantage is that it is cheap. In order to compensate for the penetration ability as much as possible, the steel core of the PAB-9 projectile is longer and heavier than the steel core of the SP-6 armor-piercing projectile, so the entire warhead is also longer and heavier.
9x39mm bullet family, note that the PAB-9 steel core head in the middle is very similar to SP-6 and BP armor-piercing bullets.
put together various 9x39mm rifle warheads, the PAB-9 warhead in the middle is the longest.
There are several 9x39mm projectile profiles. The PAB-9 projectile has the longest warhead and steel core, and the deepest shell. The
PAB-9 has been produced for a period of time, but it has not been formally installed by the Russian Army and the Ministry of Internal Affairs, so it has not been given an official GRAU serial number. When the Russian economy gradually improved, the poorly performing PAB-9 was dismissed, and production was officially stopped in 2002, so the 9A-91 assault rifles that are still in service now fired 9x39mm bullets such as SP-6 and 7N12. .
VSK-94 sniper rifle
9A-91 was finalized and put into mass production. Due to its low price and good performance, it occupied a large part of the police small assault rifle market. Similar products of the Institute of Mechanical Engineering constitute a lot of competition. Since the 9x39mm caliber small assault rifle can be successfully developed, why not go further and build on thisDevelop a micro-acoustic sniper rifle of the same caliber to form a gun family like AS micro-acoustic assault rifle and VSS micro-acoustic sniper rifle, to seize more market share? Wouldn't it be beautiful to launch a product with better performance but much lower price than the VSS micro-acoustic sniper rifle? So the Tula Instrument Design Bureau quickly designed a VSK-94 low-sound sniper rifle.
VSK-94 low-acoustic sniper rifle
VSK-94 low-acoustic sniper rifle
The core structure of the VSK-94 low-acoustic sniper rifle is exactly the same as that of the 9A-91 assault rifle. In fact, it will be on the production line. The 9A-91 with better accuracy was picked out and modified with a sporty buttstock made of plastic and integrated with the grip, even retaining the continuous firing function of the 9A-91. As a sniper rifle, of course the VSK-94 uses an optical sight as the main sight. The side rail on the left side of the receiver can be used to install Russian optical sights such as PSO-1, but as a backup, the VSK-94 retains the mechanical sight. . However, the gun's mechanical sight is slightly more complicated than 9A-91. It is not an L-shaped flipping ruler, but a cross-shaped flipping ruler. There are four divisions of 100, 200, 300, and 400m. Which notch is used to turn it. To the top.
A sporty buttstock made of plastic that is integrated with the grip
PSO-1 optical sight mounted on the side rail
A backup mechanical sight, the rear sight is mounted on a ten Which one to use on the glyph shaft?
VSK-94 micro-acoustic sniper rifle can also fire various 9x39mm rifle ammunition, but because it performs more precision shooting tasks, generally use better precision SP-5, SPP sniper ammunition. According to the actual measurement, when the VSK-94 micro-acoustic sniper rifle fires SP-5 sniper shells, the spread is 2-4 MOA at a distance of 300-400m. As a sniper rifle, it is low, but for the mission of touching the sentry and close-range raids, Basically enough.
VKS-94 sniper rifle is equipped with 9x39mmSPP sniper shell
Overall evaluation
9A-91 assault rifle and VKS-94 low-acoustic sniper rifle are very clearly positioned and designed to be built A multi-purpose gun family with performance similar to AS micro-acoustic assault rifle and VSS micro-acoustic sniper rifle. It can perform various tasks such as CQB melee, whistle and whistle sneak attack, and close-range sniper. The cost is more than AS and VSS micro-acoustic rifles. low. Russia is a country with a vast territory and uneven economic development. The military and law enforcement forces at all levels are very large. If all anti-terrorist special warfare units and reconnaissance units that need micro-sound weapons are equipped with AS and VSS micro-sound rifles, the cost is too high. Many local law enforcement agencies can’t afford it. It just so happens that the 9A-91 and VSK-94 of the Tula Instrument Design Bureau provide a good choice-low price, not bad performance, and in most cases it is enough. Therefore, among the Russian army and domestic law enforcement agencies, 9A-91 and VSK-94 often appear as cheap supplements to AS and VSS micro-sound rifles.
The VSK-94 low-acoustic sniper rifle used by Russian internal forces in the Beslan hostage incident
