VPO RPK.

The RPK (Ruchnoy Pulemyot Kalashnikova, or "Kalashnikov hand-held machine gun") is a 7.62×39mm light machine gun of Soviet design, developed by Mikhail Kalashnikov in the late 1950s, parallel with the AKM assault rifle. It was created as part of a program designed to standardize the small arms inventory of the Red Army, where it replaced the 7.62×39mm RPD light machine gun. The RPK continues to be used by the armed forces of countries of the former Soviet Union and certain African and Asian nations. The RPK is also manufactured in Bulgaria, Romania and Yugoslavia. The RPK functions identically to the AK-47. It also uses the same 7.62×39mm ammunition. It has a similar design layout to the Kalashnikov series of rifles, with modifications to increase the RPK's effective range and accuracy, enhance its sustained fire capability, and strengthen the receiver. The RPK features a heavier and longer barrel than the AKM, this allows for the weapon to be fired for extended periods without major loss in accuracy due to the barrel heating up. The chrome-lined barrel is permanently fixed to the receiver and cannot be replaced in the field. It is fitted with a new front sight base, the gas block lacks a bayonet lug and an under-barrel cleaning rod guide. The barrel also features a folding bipod mounted near the muzzle, and a front sight base with a lug that limits the bipod's rotation around the axis of the barrel. The barrel has a threaded muzzle, enabling the use of muzzle devices such as flash hiders, compensators, and blank-firing adapters. When a muzzle device is not being used, the threads on the muzzle can be covered by a thread protector. The barrel is pinned to the receiver in a modified trunnion, reinforced by ribbing, and is slightly wider than the trunnion used on the standard AKM type rifles. Symmetrical bulges on both sides of the front trunnion ensures a proper fit inside the receiver. The RPK also has a slightly longer receiver, by about 20 mm or less. This was done to decrease the fire rate slightly, but not significantly enough to lower it any less than 600 rounds per minute (RPM). The U-shaped receiver is stamped from a smooth 1.5 mm (0.06 in) sheet of steel compared to the 1.0 mm (0.04 in) sheet metal receiver used on the standard AKM rifles. It uses a modified AKM recoil spring assembly, that consists of a rear spring guide rod from the AK and a new forward flat guide rod and coil spring. It features a thick laminated wood foregrip, and a fixed laminated wood "club-foot" buttstock, similar to the stock used on the RPD, which is designed to allow the user to fire from the prone position more comfortably. It uses a standard AKM pistol grip and can also use standard AKM detachable box magazines, but it is most commonly used with a 40-round box magazine or a 75-round drum magazine. Interchangeability of parts between the RPK and AKM are moderate.