Bizon SMG

The Bizon ("Bison") is a 9mm submachine gun developed in the early 1990s at Izhmash by a team of engineers headed by Victor Kalashnikov (son of famed AK-47 designer Mikhail Kalashnikov). Alexi Dragunov, youngest son of Evgeny Dragunov (responsible for the SVD sniper rifle), was also a member of the design team.

The Bizon was developed at the request of the Ministry of Internal Affairs (MVD) and is primarily intended for counter-terrorist and law enforcement units that usually need fast and accurate fire at close ranges. Prototypes were trialed by the Special Equipment Research Institute in 1995 where they outperformed several competitors, and the weapon was accepted into service on December 28, 1996. The Bizon is issued to armed response units of the Federal Security Service (FSB) and Ministry of Justice. It was used in combat operations against separatists in the volatile North Caucasus region, namely Chechnya and Dagestan.

Design details
The Bizon is a lightweight selective fire weapon that fires from a closed bolt, a feature that enhances the gun's accuracy. It is based on the AKS-74 and features a 60% parts commonality with the assault rifle. Chambered for the standard Russian 9x18mm Makarov pistol cartridge, the gun will also fire a new high-impulse armor-piercing 57-N-181SM round.

Operating mechanism
The Bizon uses a simple straight blowback method of operation, an unlocked breech system reduces cost and build complexity. The Bizon's operating cycle is characterized by a very short recoil stroke, standard 9x18mm ammunition will only drive the bolt partially to the rear of the receiver and produces a cyclic rate of 700 rounds/min. High-impulse ammunition forces the bolt to travel all the way to the end of the receiver, barely striking the receiver wall. A rate of fire of 650–680 rounds/min is the result. This has the effect of reducing perceived recoil and increasing controllability and hit probability.

Features
The Bizon has no gas system and the internal components have been modified accordingly. The bolt carrier with integral charging handle was recycled from the AK, however the piston rod and rotary bolt were removed and the piston extension was plugged with a steel insert. The return spring and guide rod are identical to those of the AK.

The Bizon has a four-groove barrel with a 240 mm (1:9 in) right-hand rifling pitch. The gun's muzzle device has a large rectangular port on each side of dead center that serves to reduce muzzle jump, however the main purpose of this device is to protect the muzzle and magazine from damage.

The pinned and riveted sheet metal receiver of the Bizon is derived from the AKS-74 and has been modified at the front end, since the gas system was omitted. The handguard is a sheet metal stamping with three rectangular ventilation slots on each side. The magazine serves as the lower handguard and the current models of the magazine are ribbed to enhance grip. The Bizon also shares the same trigger and safety mechanisms of the AK-74 rifle. The selector lever is placed on the right side of the receiver, above the trigger, and has three settings: the uppermost "safe" setting disables the trigger and in this position the lever physically blocks the bolt's integral retracting handle; the middle position (marked "АВ") enables fully automatic fire and the lowest position ("ОД") will activate the semi-automatic function of the trigger. An original five-piece anti-bounce device is built into the trigger unit and this functions as a rate reducer, delaying firing until the bolt has settled entirely into battery.

The Bizon also utilizes the AKS-74 shoulder stock. It folds to the left side of the receiver but unlike the AKS-74 and AKS-74U, it is not held closed by a spring-loaded capture in the forward end of the receiver. Instead, it is held closed by the forward trunnion pin which is longer on the Bizon than on its AKS-74 predecessors. The extended length of the pin allows it to catch the folding skeleton stock. The pistol grip is identical to the grip on the AK-100 series and is made of a black fiberglass-reinforced polyamide.

Feeding


One of the Bizon's more unusual features is the magazine, which is often confused for a grenade launcher. The cylinder below the barrel is in fact a 64-round helical-feed magazine, similar to the type used in the American Calico M960 submachine gun. The magazine is made from a durable glass-reinforced polyamide and mounts under the handguard in line with the barrel. This layout makes the weapon more compact and concealable. All cartridges are aligned nose forward in the Bizon magazine and cannot be loaded incorrectly. Early magazines were fabricated from aluminium tubing and had a capacity of 67 rounds. The production magazine capacity of 64 was selected as 64 is a multiple of 16, and 9x18mm Makarov rounds are packaged in boxes of 16. The magazine has hooks on top of the front end that engage a pair of pins under the front sight, and the rear end of the magazine interfaces with a Kalashnikov pattern spring-loaded paddle type magazine catch/release located in front of the trigger guard. Some magazines were produced with indicator holes allowing the user to verify the amount of ammunition loaded; these are spaced at 4, 24, 44 and 64-round increments.

Sights


The sighting arrangement resembles that used on the AKS-74U and consists of a rear flip-up sight permanently attached to the receiver top cover with two open square notches with 50 and 100 m elevation settings and a round post front sight taken from the AK series of rifles, common to many Russian small arms. The front sight is contained in a protective hood with a hole in the top to insert an elevation adjustment tool, while the rear sight is shielded by two metal ears.

Accessories
The gun is issued with one magazine, a sling, cleaning kit, oil can and magazine pouch. Other accessories such as scope mounts, Kobra optics and PBS1 silencers were available due to it being largely derived from the AK74/47 family, thus having the correct thread and AK optics side mount.

Variants
The original Bizon was retroactively designated Bizon-1 after the design was improved with the introduction of the Bizon-2.

Bizon-2


The Bizon has been continuously modified over its production life and the current model is the Bizon-2, which has AK-style iron sights (an open U-notch rear sight on a tangent with three settings: 50, 100 and 150 m and a semi-shrouded front post), a receiver-mounted side rail adapter for optics and a new slotted flash hider designed to accept a quick-detachable sound suppressor. The Bizon-2 is made in several variants to increase the product's commercial appeal and demonstrate its versatility; it is offered in 8 different configurations:


 * Bizon-2-01: Chambered for the NATO-standard 9x19mm Parabellum cartridge using a modified magazine with a 53-round capacity.
 * Bizon-2-02: Chambered in the .380 ACP (9x17mm Short) pistol round (64-round magazine capacity).
 * Bizon-2-03: 9x18mm Makarov variant with an integral sound suppressor.
 * Bizon-2-04: 9x18mm Makarov semi-automatic carbine model.
 * Bizon-2-05: 9x19mm Parabellum semi-automatic only model.
 * Bizon-2-06: Semi-automatic only carbine version in .380 ACP (9x17mm Short).
 * Bizon-2-07: Select-fire model chambered in 7.62x25mm Tokarev. This model dispenses with the Bizon's helical magazine and uses a conventional staggered-column 35-round steel magazine.

Bizon-3
A variant known as the Bizon-3 was also developed, and features a flip-up rear peep sight moved further to the rear on the receiver cover and a stock that folds up and over the receiver to lock into a spring-loaded latch on the receiver top cover. The weapon's barrel has an adapter for several types of muzzle devices. These are selected by the operator depending on the weapon's tactical employment and include sound suppressors, muzzle brakes, compensators and flash hiders.