The AK-74 was designed by А.D. Kryakushin's group under the design supervision of Mikhail Kalashnikov and 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-caliber 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 to the preceding AKM the AK-74 has better effective range, firing accuracy (a main development goal) and reliability. The AK-74 and AKM share an approximate 50% parts commonality (interchangeable most often are pins, springs and screws).
Relatively small sized, light weight, high velocity military service cartridges like the 5.45×39mm allow a soldier to carry more ammunition for the same weight compared to their larger and heavier predecessor cartridges, have favourable maximum point-blank range or "battle zero" characteristics and produce relatively low bolt thrust and free recoil impulse, favouring light weight arms design and automatic fire accuracy. Tests measured the free recoil energy delivered by the 5.45×39mm AK-74 rifle at 3.39 J (2.50 ft·lb), compared to 7.19 J (5.30 ft·lb) delivered by the 7.62×39mm in the AKM.
Early 5.45×39mm ballistics tests demonstrated a pronounced tumbling effect with high speed cameras. Some Western authorities believed this bullet was designed to tumble in flesh to increase wounding potential. At the time, it was believed that yawing and cavitation of projectiles were primarily responsible for tissue damage. Martin Fackler conducted a study with an AK-74 assault rifle using live pigs and ballistic gelatin; "The result of our preset test indicate that the AK-74 bullet acts in the manner expected of a full-metal-cased military ammunition - it does not deform or fragment when striking soft tissues". Most organs and tissue were too flexible to be severely damaged by the temporary cavity effect caused by yaw and cavitation of a projectile. With the 5.45 mm bullet, tumbling produced a temporary cavity twice, at depths of 100 mm (3.9 in) and 350 mm (13.8 in). This is similar to (but more rapid than) modern 7.62×39mm ammunition and to (non-fragmenting) 5.56×45mm NATO ammunition.
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) 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. 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 armory before issue or if the need arises by an armorer 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" on the 5.45×39mm AK-74 rear tangent sight element corresponds to a 400 m (437 yd) zero, compared to 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 limits the apparent "bullet rise" within approximately −5 to +40 cm (−2.0 to 15.7 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.
While most Russian and CIS armed forces use the iron sights on the AK-74, many magnifying and non magnifying optical sights are available for designated marksman, Spetsnaz and other special purpose troops in their prospective militaries.
For the 5.45×39mm AK-74, the East German Zeiss ZFK 4×25, 1P29, Belorussian BelOMO PO 3.5×21P, PO 4×24P and the 1P78 Kashtan dedicated side rail mounted optical sights were developed. These optical sights are primarily designed for rapid target acquisition and first round hits out to 400 m, but by various means these optical sights also offer bullet drop compensation (BDC) (sometimes referred to as ballistic elevation) for aiming at more distant targets. The BDC feature compensates for the effect of gravity on the bullet at given distances (referred to as "bullet drop") in flat fire scenarios. The feature must be tuned for the particular ballistic trajectory of a particular combination of gun and cartridge at a predefined muzzle velocity and air density. Since the usage of standardized ammunition is an important prerequisite to match the BDC feature to the external ballistic behaviour of the employed projectiles, these military optical sights are intended to assist with field shooting at varying medium to longer ranges rather than precise long range shots.
The standard Russian side rail mounted optical sight was the 4×26 1P29 Universal sight for small arms, an aiming optic similar to the British SUIT and SUSAT and Canadian C79 optical sights. When mounted the 1P29 sight is positioned centered above the receiver at a height that allows the use of the iron sights. It weighs 0.8 kg, offers 4× magnification with a field of view of 8° and 35 mm eye relief. The 1P29 is issued with a canvas pouch, a lens cleaning cloth, combination tool, two rubber eyecups, two eyecup clamps and three different bullet drop compensation (BDC) cams for the AK-74, RPK-74 and PK machine gun. The 1P29 is intended for quickly engaging point and area targets at various ranges and is zeroed for both windage and elevation at 400 m (437 yd). On the right side of the field of view a stadiametric rangefinder is incorporated that can be used to determine the distance from a 1.5 meters (4 ft 11.1 in) tall object from 400 to 1,200 m (437 to 1,312 yd). The reticle is an inverted aiming post in the top half of the field of view and is tritium-illuminated for low-light condition aiming.
The current Russian standard side rail mounted optical sight for the AK-74M is the 2.8×17 1P78 Kashtan, an aiming optic more similar to the American ACOG. When mounted the 1P78 sight is positioned centered above the receiver. It weighs 0.5 kg, offers 2.8× magnification with a field of view of 13° and 32 mm eye relief. The 1P78 comes in several versions for the AK-74 (1P78-1), RPK-74 (1P78-2), AKM (1P78) and RPK (1P78-3). The 1P78 is intended for quickly engaging point and area targets at various ranges and is zeroed for both windage and elevation at 400 m (437 yd). A stadiametric rangefinder is incorporated that can be used to determine the distance for a soldier sized target from 400 to 700 m (437 to 766 yd). The reticle consist of a main 400 m "chevron" (^), a 500 m (547 yd) holdover dot and smaller additional holdover chevrons for 600 m (656 yd) and 700 m (766 yd) and is tritium-illuminated for low-light condition aiming.
The AK-74 was equipped with a new buttstock, handguard (which retained the AKM-type finger swells) and gas cylinder. The stock has a shoulder pad different from that on the AKM, which is rubber and serrated for improved grip. In addition, there are lightening cuts on each side of the buttstock. The buttstock, lower handguard and upper heatguard were first manufactured from laminated wood, this later changed to a synthetic, plum or dark brown colored fiberglass.
The AK-74 gas tube has a spring washer attached to its rear end designed to retain the gas tube more securely. The lower handguard is fitted with a leaf spring that reduces play in the rifle's lateral axis by keeping the wood tensioned between the receiver and the handguard retainer. The receiver remains nearly identical to that of the AKM; it is a U-shaped 1 mm (0.04 in) thick sheet steel pressing supported extensively by pins and rivets. The internal guide rails on which the bolt carrier travels are stamped and spot welded to the inside of the receiver housing. Minor changes were made to the front barrel and rear stock trunnions as well as the magazine well. All external metal surfaces are coated with a glossy black enamel paint.
The original steel-reinforced 30-round AK-74 detachable box magazine was similar to that of the AKM, except for minor dimensional changes required by the 5.45×39mm cartridge. These rust-colored magazines are often mistakenly identified as being made of Bakelite (a phenolic resin), but were actually fabricated from two-parts of AG-S4 molding compound (a glass-reinforced phenol-formaldehyde binder impregnated composite), assembled using an epoxy resin adhesive. Noted for their durability, these magazines did however compromise the rifle's camouflage and lacked the small horizontal reinforcing ribs running down both sides of the magazine body near the front that were added on all later AK-74 magazine generations. A second generation steel-reinforced dark-brown (color shades vary from maroon to plum to near black) 30-round magazine was introduced in the early 1980s, fabricated from ABS plastic. The third generation steel-reinforced 30-round AK-74 magazine is similar to the second generation, but is darker colored and has a matte nonreflective surface finish. With the introduction of the AK-74M the fourth generation of steel-reinforced matte true black nonreflective surface finished 30-round AK-74 magazines was introduced. All AK-74 magazines have a raised horizontal rib on each side of the rear lug to prevent their use in a 7.62×39mm AK. The magazines can be quickly recharged from stripper clips. The empty weight of a 30-round AK-74 box magazine is 230 g (8.1 oz). The 45-round plastic box magazine of the RPK-74 light machine gun is also interchangeable with that of the AK-74. The empty weight of a 45-round RPK-74 box magazine is 300 g (11 oz). Further 60-round and later 50-round quad-stack 5.45×39mm casket magazines were developed.
The transition to mainly plastic magazines and the relatively small sized, light weight, high velocity 5.45×39mm cartridge yielded a significant weight reduction and allow a soldier to carry considerably more rounds for the same weight compared to the previous Soviet AK-47 and AKM and later 7.62×39mm chambered AK platform assault rifles.
Note: All, 7.62×39mm AK magazines are backwards compatible with older AK variants.
Note *: 10.12 kg (22.3 lb) is the maximum amount of ammo that the average soldier can comfortably carry... it also allows for best comparison of the three most common 7.62×39mm AK platform magazines and the 5.45×39mm AK-74 magazine.
Accessories supplied with the rifle include a 6H4 or 6H5 type bayonet, a quick-loading device, three spare magazines, four 15-round stripper clips, maintenance kit, cleaning rod and sling. The bayonet is installed by slipping the muzzle ring around the flash hider and latching the handle down on the bayonet lug under the front sight base. The 6H5 AK-74 bayonet introduced in 1983 represents a further refinement of the 6H4 AKM bayonet. It introduced a radical blade cross-section, that has a flat milled on one side near the edge and a corresponding flat milled on the opposite side near the false edge. The blade has a new spear point and an improved one-piece molded plastic grip making it a more effective fighting knife. It also has saw-teeth on the false edge and the usual hole for use as a wire-cutter.
The AKS-74 ("S"—Russian: складной; Skladnoy, or "folding"), 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.
In 1973, a design competition (codenamed "Modern"—Модерн) was started for the adoption of a fully automatic carbine.
This was no doubt inspired by observing the US experience in Vietnam with the XM177. The Soviet planners also 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 M.T. Kalashnikov (PP1), I.Y. 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 it was no worse than the competition in terms of performance, and promised significant production cost savings by utilizing existing equipment for the AK-74 line. A final round of large scale testing with Kalashinkov'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. In 1993 production stopped.
In terms of tactical deployment, the AKS-74U bridges the 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 rifle's compact dimensions, compared to the AKS-74, 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 of fire rose slightly to 700 rd/min. In order to effectively stabilize projectiles, the barrel's twist rate was increased from 200 mm (1:7.87 in) to 160 mm (1:6.3 in) 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 gasses 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 stored under the barrel. The forward sling loop was relocated to the left side of the carbine and the front sight was integrated into the gas block.
The AKS-74U also has a different sighting system with a U-shaped flip sight instead of the standard sliding notch tangent rear sight. This rear sight has two settings: "П" 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 the barrel trunnion, 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 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 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).
In the United States, the AKS-74U is called a "Krinkov". The origin of this term is uncertain. A hypothesis was circulating that the name came from the mujahadeen who supposedly had captured a high-ranking Soviet officer armed with an AKS-74U, and that they had named it after him. However, investigation by Patrick Sweeney could not confirm this hypothesis, for no Soviet officer with a resembling name was captured in Afghanistan. US journalist C. J. Chivers reported that the gun was nicknamed "the Osama" in jihadist circles, after Osama bin Laden was photographed next to an AKS-74U. Research by The Firearm Blog published in 2016 suggests that the name "Krinkov" is actually a Pashtun invention that came to the United States with accounts of the Mujahideen.
The AK-74 is also available in several "night-fighting" configurations, equipped with a side-rail used to mount night vision scopes. These variants, the AK-74N, AKS-74N and AKS-74UN can be used in conjunction with NSPU and NSPU-3 (1PN51) scopes. The variants designated AK-74N2 and AKS-74N2 can use the multi-model night vision scope NSPUM (1PN58). The AKS-74UB ("B"—Russian: бесшумный; Besshumniy or "silent") is a sound-suppressed variant of the AKS-74U adapted for use with the PBS-4 suppressor (used in combination with subsonic 5.45×39mm Russian ammunition). Very little is known about this model.
In 1991 the Izhmash factory in the city of Izhevsk began full-scale production of a modernized variant of the AK-74—the AK-74M (M—Russian: Модернизированный; Modernizirovanniy or "modernized") assault rifle that offers more versatility compared to 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 skeletonized AKS-74 buttstock. Additionally the AK-74M features an improved muzzle device, 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. Each AK-74M is fitted with a side-rail bracket for mounting optics. 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.
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 May 9, 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.
The AK-74M was also the basis for the new Russian AK-100 family of Kalashnikov firearms: the AK-101 assault rifle and AK-102 carbine (both chambered for the NATO-standard 5.56×45mm NATO cartridge), AK-103 assault rifle and AK-104 carbine (both chambered for the 7.62×39mm round) and the 5.45×39mm AK-105 carbine. The AK-101, AK-102, AK-103 and AK-104 are destined primarily for export, while the AK-105 is slated to replace the AKS-74U with the Russian Armed Forces. Additionally, the 5.45×39mm AK-107 and 5.56×45mm NATO AK-108 rifles have a balanced recoil system to reduce felt recoil and muzzle rise. This balanced recoil system is derived from the AL-7 rifle.
In 2010 a new variant, the AK-12 series, was unveiled. It differs in weight, introduces a new recoil compensation technology, and has improved ergonomics. The rear iron sight is rail-mounted and is moved all the way to the back of the upper receiver for enhanced accuracy, and the full top length of the weapon is covered in a Picatinny rail for easy mounting of accessories such as aftermarket iron sights and optics while the handguard has Picatinny rails on both sides and on its underside for mounting of tactical lights, laser sights and grenade launchers.
The following table represents the Russian method for determining accuracy and it is far more complex than Western methods. In the West, one fires a group of shots into the target and then simply measure the overall diameter of the group. The Russians on the other-hand, fire a group of shots into the target. They then draw two circles on the target. One for the maximum vertical dispersion of hits and one for the maximum horizontal dispersion of hits. They then disregard the hits on the outer part of the target and only count half of the hits (50% or R50) on the inner part of the circles. This dramatically reduces the overall diameter of the groups. They then use both the vertical and horizontal measurements of the reduced groups to measure accuracy. This method cannot be converted and is not comparable to western methods for determining accuracy.R50 means the closest 50 percent of the shot group will all be within a circle of the mentioned diameter.
In general, this is an improvement with respect to firing accuracy to the AK-47 and the AKM. The vertical and horizontal mean (R50) deviations with service ammunition at 800 m (875 yd) for AK platforms are.
The single-shot hit-probability on the NATO E-type Silhouette Target (a human upper body half and head silhouette) of the AK-47, AK-74 and M16A1 and M16A2 assault rifles were measured by the US military under ideal proving ground conditions in the 1980s as follows:
Under worst field exercise circumstances, due to range estimation and aiming errors, the hit probabilities for the tested assault rifles were drastically reduced with differences without operational significance.R50 means the closest 50 percent of the shot group will all be within a circle of the mentioned diameter.
Afghanistan The Mujihadeen nicknamed it the "Kalakov."
Armenia AK-74 is currently the main service rifle of the Armenian armed forces.
Azerbaijan: AK-74M manufactured under license by the Ministry of Defence Industry of Azerbaijan.
Bulgaria: AR-M1 (variation of AK-74) and AKS-74U are manufactured locally.
China: Locally produced as Type-88 and Type-88-1.
Cyprus: The AK-74M is used by the Cypriot National Guard (Greek-Cypriot forces)
Georgia: In use alongside the M4 carbine in service in Georgia.
East Germany: Manufactured locally as the MPi-AK-74N, MPi-AKS-74N and MPi-AKS-74NK.
Latvia AKS-74 and AKS-74U used by Latvian State Police and Customs services.
North Korea Manufactured locally as the Type-88 and Type-88-1.
Poland: Kbk wz. 1988 Tantal manufactured locally, retired in 2005, some sold to Iraq.
Romania: Manufactured locally as the PA md. 86.
Russia: AK-74M is currently the main service rifle in the Russian Army.
Soviet Union: First used during the Soviet–Afghan War in 1979.
Vietnam: North Korean Type-98 and Type-98-1 used by the Vietnam People's Navy.