AK-74

The **AK-74** is an assault rifle manufactured by Kalashnikov Concern.

## Overview

The AK-74 was designed by А. D. Kryakushin's group under the design supervision of Mikhail Kalashnikov. It is an adaptation of the 7.62×39mm AKM assault rifle and features several important design improvements. These improvements were primarily the result of converting the rifle to the intermediate-calibre high velocity 5.45×39mm cartridge. In fact, some early models are reported to have been converted AKMs, re-barreled to 5.45×39mm. Compared with the preceding AKM, the AK-74 has better effective firing range, accuracy (a main development goal), and reliability. About 50% of the parts in the AK-74 and AKM are the same (including pins, springs and screws).

The rifle's operation during firing and reloading is identical to that of the AKM. After ignition of the cartridge primer and propellant, rapidly expanding propellant gases are diverted into the gas cylinder above the barrel through a vent near the muzzle. The build-up of gases inside the gas cylinder drives the long-stroke piston and bolt carrier rearward and a cam guide machined into the underside of the bolt carrier along with an ejector spur on the bolt carrier rail guide, rotates the bolt approximately 35° and unlocks it from the barrel extension via a camming pin on the bolt. The moving assembly has about 5.5 mm (0.2 in) of free travel which creates a delay between the initial recoil impulse of the piston and the bolt unlocking sequence, allowing gas pressures to drop to a safe level before the seal between the chamber and the bolt is broken. Like previous Kalashnikov-pattern rifles, the AK-74 does not have a gas valve; excess gases are ventilated through a series of radial ports in the gas cylinder. Since the Kalashnikov operating system offers no primary extraction upon bolt rotation, the 5.45×39mm AK-74 bolt has a larger extractor claw than the 7.62×39mm AKM for increased extraction reliability. Other minor modifications were made to the bolt and carrier assembly.

The rifle received a new barrel with a chrome-lined bore and 4 right-hand grooves at a 200 mm (1:7.87 in) or 37 calibers rifling twist rate. The front sight base and gas block were redesigned. The gas block contains a gas channel that is installed at a 90° angle in relation to the bore axis to reduce bullet shear at the port hole. A pair of support brackets are cast into the gas block assembly and are used to attach a BG-15c or GP-25 underslung 40 mm grenade launcher. Like the AK-47 and AKM, the muzzle is threaded for the installation of various muzzle devices such as the standard muzzle brake or a blank-firing adaptor, while a spring-loaded detent pin held in the front sight post prevents them from unscrewing while firing. However the muzzle threads have been relocated to the front sight base for both easier and more economic replacement in case of thread damage. The distinctive standard-issue muzzle brake features a large expansion chamber, two symmetrical vertical cuts at the forward end of the brake and three non symmetrical positioned vent holes to counteract muzzle rise and climb as well as lateral shift to the right much like the AKM's offset muzzle brake. A flat plate near the end of the brake produces a forward thrust when emerging exhaust gases strike its surface, greatly reducing recoil. The muzzle brake prevents backblast from reaching the firer, although it is reported to be harsh on bystanders as the muzzle gases are dispersed to the sides. The standard-issue AK-74 muzzle brake has been subtly revised several times since the 1970s.

The AK-74 uses an adjustable notched rear tangent iron sight calibrated in 100 m (109 yd) increments from 100 to 1,000 m (109 to 1,094 yd). The front sight is a post adjustable for elevation in the field. Horizontal adjustment requires a special drift tool and is done by the armoury before issue or if the need arises by an armourer after issue. The sight line elements are approximately 48.5 mm (1.9 in) over the bore axis. The "point-blank range" battle zero setting "*П*" standing for *постоянная* (constant/consistent/permanent) the 5.45×39mm AK-74 rear tangent sight element corresponds to a 400 m (437 yd) zero, compared with the 300 m (328 yd) zero for 7.62×39mm AKs. For the AK-74 combined with the 7N6 or 7N10 service cartridges the 400 m battle zero setting point-blank range limits the apparent "bullet rise" within approximately −5 to +38 cm (−2.0 to 15.0 in) under the line of sight. At the corresponding 440 m (481 yd) maximum point-blank range the bullet will have dropped to approximately −21 cm (−8.3 in) relative to the line of sight. Soldiers are instructed to fire at any target within this range by simply placing the sights on the center of mass (the belt buckle, according to Russian and former Soviet doctrine) of the enemy target. Any errors in range estimation are tactically irrelevant, as a well-aimed shot will hit the torso of the enemy soldier.

## Variants

The AK-74 series is also available in several "night-fighting" configurations, equipped with a side dovetail rail for mounting optical sights. These variants, the **AK-74N**, **AKS-74N** and **AKS-74UN** can be used in conjunction with NSPU and NSPU-3 (1PN51) night sights, as well as optical sights such as the USP-1 (1P29). The variants designated AK-74N2 and AKS-74N2 can use the multi-model night vision sight NSPUM (1PN58).

### AKS-74

The **AKS-74** ("S"—Russian: складной; *Skladnoy*, or "foldable"), is a variant of the AK-74 equipped with a side-folding metal shoulder stock, designed primarily for use with air assault infantry and developed alongside the basic AK-74. Unlike the AKMS's somewhat fragile underfolding stock (modeled after the MP 40 submachine gun stock), the AKS-74 stock is fabricated from stamped sheet metal struts, machine pressed into a "U" shape and assembled by punch fit and welding.

The stock has a triangular shape; it lacks the folding shoulder pad found on the AKMS stock and is folded to the left side of the receiver. The hinged stock is securely locked in its extended position by a spring-loaded button catch located at the rear of the receiver. When folded, the stock is held closed by a spring-loaded capture hook situated on the left side at the front of the receiver housing. A rear-mounted sling swivel is also provided on the right side at the beginning of the stock frame. It retains the pistol grip reinforcement plate the AKMS used, though due to the less complex rear trunnion, only has one riveting hole in place of the three on the AKMS.

### AK-74M

In 1991, the Izhmash factory in the city of Izhevsk began full-scale production of a modernised variant of the AK-74—the **AK-74M** ("М"—Russian: Модернизи́рованный, tr. *Modernizírovanny*, lit. 'modernised') assault rifle that offers more versatility compared with its predecessor. Apart from several minor improvements, such as a lightened bolt and carrier assembly to reduce the impulse of the gas piston and bolt carrier during firing, the rifle features a new glass-filled polyamide stock that retains the shape of the original AK-74 fixed laminated wood stock, but side-folds to the left like the skeletonised AKS-74 buttstock. As a result, pistol grip reinforcement plates that were once exclusively used on the folding stock variants are standard on all AK-74Ms. Additionally the AK-74M features an improved muzzle device with extended collar and threads to reduce play and a machine cut beneath to allow easier cleaning rod removal, a reinforced smooth dust cover and a redesigned guide rod return spring retainer that allows firing the GP-25, GP-30 and GP-34 underslung grenade launchers without having to use the previously necessary additional receiver cover fastener. To reduce production costs, barrel hardware, such as the front sight base and gas block, are dimple pressed on to the barrel instead of pinned on (commercial semi-auto variants are still pinned on to maintain user serviceability).

Other economic changes include omission of lightening cuts on the front sight block and gas piston as well as a stamped gas tube release lever, replacing the milled one. The bullet guide and bolt guide were also separated, with the bolt guide becoming a simple bump held in place on the left side of the receiver with an additional rivet (often called a "bump rivet" because of this) making it easier to replace in case of wear. Each AK-74M is fitted with a side-rail bracket for mounting optics that is a simplified version of the 74N mount with less machining cuts. The AK-74M would have been adopted by the Soviet Union as the standard service rifle, and has been accepted as the new service rifle of the Russian Federation.

### AK-74M UUK (Universal Upgrade Kit)

An AK-74M universal upgrade kit consisting of a new safety, dust cover and furniture featuring improved ergonomics and rails to attach accessories like aiming optics, optoelectronic sights, laser sights, weapon lights and vertical fore grips and a new muzzle device had its official debut on 9 May 2015 in Moscow as part of the 2015 Moscow Victory Day Parade. The Kalashnikov Concern has further developed three sets of additional equipment for the modernization of 5.45×39mm and 7.62×39mm chambered AK-pattern assault rifles for normal military units, reconnaissance units, and special forces units.

The Kalashnikov Concern announced it has a contract with the Russian Ministry of Defence to deliver upgrade kits for their AK-74M assault rifles.

## AKS-74U

In 1973, a design competition (codenamed "Modern"—Модерн) was started for the adoption of a fully automatic carbine.

Soviet planners drew from the unsolicited design AO-46 built in 1969 by Peter Andreevich Tkachev, which weighed only 1.9 kg. The TTT specifications required a weight no greater than 2.2 kg (4.9 lb), a length of 75 cm (29.5 in)/45 cm (17.7 in) with the stock unfolded/folded, and an effective firing range of 500 m (547 yd). The competition was joined by designs of Mikhail Kalashnikov (PP1), Igor Stechkin (TKB-0116), S. G. Simonov (AG-043), A. S. Konstantinov (AEK-958), and Yevgeny Dragunov (who called his model "MA"). Kalashnikov also presented an additional design (A1-75) which differed from PP1 by having a modified muzzle for flash and noise suppression.

In 1977, the GRAU decided to adopt Kalashnikov's model, which was largely a shortened AKS-74, because its performance was no worse than the competition, and promised significant production cost savings by utilizing existing equipment for the AK-74 line. A final round of large scale testing with Kalashnikov's model was performed by airborne divisions in the Transcaucasian Military District in March 1977. The AKS-74U ("U"—Russian: укороченный; *Ukorochenniy*, or "shortened") was officially adopted in 1979, and given the official, but seldom used GRAU designation 6P26. Production stopped in 1993.

The AKS-74U bridges the tactical deployment gap between a submachine gun and an assault rifle. It was intended for use mainly with special forces, airborne infantry, rear-echelon support units, helicopter and armored vehicle crews. It has been augmented and replaced by various submachine guns, and the less compact AK-105 carbine in Russian military service. It is commonly used by law enforcement; for example, each urban police foot patrol is issued at least one.

The AKS-74U's compact dimensions were achieved by using a short 206.5 mm (8.1 in) barrel (this forced designers to simultaneously reduce the gas piston operating rod to an appropriate length). Due to the shortening of the operating mechanism, the cyclic rate rose slightly to around 700 rounds per minute. In order to effectively stabilize projectiles, the barrel's twist rate was increased from 200 mm (1:7.87 in) or 37 calibers rifling twist rate to 160 mm (1:6.3 in) or 29.6 calibers rifling twist rate to adapt the AKS-74U for muzzle velocities of 720 m/s (2,362 ft/s) and higher. A new gas block was installed at the muzzle end of the barrel with a muzzle booster, which features an internal expansion chamber inside the cylindrical section of the booster while the conical end acts as a nozzle to increase net pressure inside the gas chamber by supplying an increased amount of propellant gases from the barrel. The chrome-lined muzzle booster also burns any remaining propellant, which would normally reduce muzzle blast. However, due to the extremely short barrel and conical end of the booster, the muzzle blast is nevertheless extremely large and visible. The muzzle device locks into the gas block with a spring-loaded detent pin and features two parallel notches cut into the edge of the flash hider cone, used for unscrewing it using the cleaning rod. Unlike most Kalashnikov variants there is no provision to store the cleaning rod under the barrel. The front sight was integrated into the gas block/forward sling loop.

The sight height above the bore axis is also approximately 3 mm (0.1 in) higher than the AK-74, due to the combined front sight/gas block, rear sight configuration. The AKS-74U has a different rear sight composed of a U-shaped flip sight on the top cover instead of the standard sliding notch tangent rear sight. This rear sight has two settings: "*П*" standing for *постоянная* (constant) corresponding to a 350 m (383 yd) "point-blank range" battle zero setting and "4-5" (used for firing at distances between 400–500 m (437–547 yd)). The rear sight is housed in a semi-shrouded protective enclosure that is riveted to the receiver's spring-loaded top cover. This top cover hinges from a barrel trunnion (hinging where the rear sight on a normal AK74 is located), pivoting forward when opened, which also works to unlock the gas tube cover. Both the gas tube and handguard are also of a new type and are wider and shorter than the analogous parts in the AKS-74.

For the AKS-74s combined with the 7N6 or 7N10 service cartridges the 350 m battle zero setting limits the apparent "bullet rise" within approximately −5 to +42 cm (−2.0 to 16.5 in) relative to the line of sight. Soldiers are instructed to fire at any target within this range by simply placing the sights on the center of mass (the belt buckle) of the enemy target. Any errors in range estimation are tactically irrelevant, as a well-aimed shot will hit the torso of the enemy soldier.

The AKS-74U is significantly more maneuverable in tight quarters than the AKS-74; however, the significant decline in muzzle velocity to 735 m/s (2,411 ft/s) resulted in a 100 m (109 yd) reduction in effective range to 400 m (437 yd) (the effective hitting distance for a "running"-type silhouette target was reduced from 625 m (684 yd) to 360 m (394 yd)). The AKS-74U cannot mount a bayonet or standard under-barrel grenade launcher. However, a suppressed 30 mm BS-1 grenade launcher was developed specifically for that platform that fires a high-explosive dual purpose (HEDP) grenade. The grenades for the BS-1 are launched by special blank cartridges that are inserted into the grenade launcher via a detachable magazine. The majority of AKS-74U carbines were manufactured at the Tula Arms Factory rather than Izhmash. There were some accessories produced for the AKS-74U including a plastic thigh holster and (shorter than standard) 20-round AK-74 type magazines. The rifle utilizes a proprietary 25 mm wide sling that differs from the standard 35 mm AK sling also in construction. The AKS-74U also exists in a version featuring modernized synthetic furniture made from a black, glass-filled polyamide. The AKS-74U was also used as the basis for several other unique weapons, including the bullpup OTs-14 Groza specialist carbine which is now in limited service in the Russian military, and the Gepard series of multi-caliber submachine guns (none of which evolved past prototype stage).

### Users

* Iron Clad Mercenaries (AK-74M variant)
* Task Force Zeta (AKS-74U variant)