The original AK was also known as the AK-47. It was a gas-operated, selective-fire weapon. Like all 7.62-mm Kalashnikov assault rifles, it fired the Soviet 7.62 x 39-mm M1943 round and used a standard 30-round curved box magazine. The AK came in two versions: one with a fixed wooden stock, and another, the AKS, with a folding metal stock issued primarily to parachutist and armor troops. Except for the differences in the stock and the lack of a tool kit with the AKS, the two version were identical. The early AKs had no bayonet, but the version with the fixed wooden stock later mounted a detachable knife bayonet.
The improved model, known as the AKM, is easier to produce and operate. It weighs about one kilogram less than the AK. The reduced weight results from using thinner, stamped sheetmetal parts rather than machined, forged steel; laminated wood rather than solid wood in the handguard, forearm, pistol grip, and buttstock; and new lightweight aluminium and plastic magazines. Other improvements include a straighter stock for better control; an improved gas cylinder; a rate-of-fire control alongside the trigger; a rear sight graduated to 1,000 meters rather than 800 meters; and a greatly improved, detachable bayonet.
The AKM also has a folding-stock version, designated AKMS, intended for use by riflemen in armored infantry combat vechicles such as the BMP. Except for its T-shaped, stamped-metal, folding buttstock, the AKMS is identical to the AKM. The folding-stock model can reduce its length from 868 to 699 millimeters.
All 7.62-mm Kalashnikov assault rifles fire in either semiautomatic or automatic mode and have an effective range of about 300 meters. At full cyclic rate, they can fire about 600 rounds per minute (upto 640 rounds per minute for the AKM), with a practical rate of about 100 rounds per minute fully automatic or 40 rounds per minute semiautomatic. Both the AK and AKM can mount a grenade launcher. Both can have passive image intensifier night sights. Both can function normally after total immersion in mud and water. The fully chromed barrel ensures effective operation even at very low temperatures. The muzzle of either weapon fits into the swiveling firing points of the BMP. Thus, the infantryman can fire the weapon while the vechicle is moving.
The most serious drawback to the AK and AKM is the low muzzle velocity (710 meters per second) of the relatively heavy 7.62-mm round. This results in a looping trajectory that requires a clumsy adjustment for accuracy at ranges beyond 300 meters. The barrel overheats quickly when the weapon fires for extended periods, making the weapon hard to handle and occasionally causing a round to explode prematurely in the chamber. The exposed gas cylinder is easily dented, sometimes causing the weapon to malfunction.
Although they designed it in 1947 and thus referred to it as the AK-47, the Soviets actually adopted the AK in 1949. The AK entered service in 1951. It was the basic individual infantry weapon of the Soviet Army until the introduction of the AKM. The Soviets developed the AKM in 1959. It entered service in 1961. All 7.62-mm Kalashnikov assualt rifles are very dependable weapons. They produce a high volume of fire and are simple to maintain. However, the new 5.45-mm assault rife AK-74 is replacing the 7.62-mm weapons.
The following data comes from Janes Infantry Weapons 1995 – 1996.
Cartridge: 7.62 x 39 mm Operation: gas, selective fire
Locking: rotating bolt Feed: 30-round detachable box magazine
Weight: 4.3 kg Length: 869 mm
Barrel: 414 mm Rifling: 4 grooves, rh, 1 turn in 235 mm
Sights: fore, post, adjustable; rear, U-notch, tangent Muzzle velocity: 710 m/s
Rate of fire: cyclic, 600 rds/min Effective range: 300 m