Caliber 7,62×39 mm
Weight 4,8 kg empty
Length 1040 mm
Length of barrel 590 mm
Feeding box magazine 40 rounds, or drum 75 rounds
Rate of fire 600 rounds per minute
In mid-1950s Soviet army started trials for a new infantry weapons system to replace the 7.62×39 SKScarbines, AKassault rifles and RPD LMGs.Several designers submitted their designs, which included both assault rifle and machine rifle / LMG – basically the same weapon as the companion rifle but with a longer, heavier barrel and with larger capacity, but still compatible, magazines. In 1961, Soviet army has chosen the Kalashnikov system, comprising of a modified AKM assault rifle and RPK squad automatic weapon (machine rifle / light machine gun). RPK stands for Ruchnoy Pulemjot Kalashnikova– Kalashnikov hand-held (light) machine gun. Copies of the RPK were orstill are produced in several countries, that also made AK type rifles;in Russia RPK light machine guns were mostly replaced in service by5,45mm RPK-74 light machine guns of similar design, although few 7,62mm RPK may be still found in service with non-infantry units. Also, for export purposes, Russia produces 7,62mm RPKM light machine guns, which use same polymer furniture as RPK-74M but chambered for old 7,62×39 ammunition.
The RPK is a gas operated, magazine fed, air cooled, selective fire weapon.The basic action, with a long-stroke gas piston located above the barrel and a rotating bolt, is similar to that of the Kalashnikov assault rifle. The trigger unit and safety is also the same,therefore the RPK fires from a closed bolt in both semi-automatic and automatic modes. The barrel is permanently fixed to the receiver and cannot be replaced in the field.
Ammunition feed is from magazines only.The magazine interface is same as on the Kalashnikov assault rifle in the same caliber, and RPK and AKM magazines are interchangeable. However, the standard magazines for RPK are of extended capacity. The most common are curved box magazines holding 40 rounds of ammunition. Early production RPK magazines were made from stamped steel, but later on polymer magazines wer eintroduced. Steel drum magazines were also produced for the RPK. These magazines were rather heavy and expensive to make, and loaded same way as box magazines, by inserting rounds one by one through the magazine mouth(which can be a rather boring procedure, especially if several magazines need to be filled at once). Those drum magazines held 75 rounds of ammunition.
Standard sights of RPK are basically similar to that of the AKM rifle, with hooded post front and tangent type rear sight, marked for ranges between 100 and 1000 meters. However, the RPK rear sight also includes a windage adjustment mechanism. Special versions with an“N” suffix in the designation (RPKN,) were fitted with a side rail on the receiver to accept mountings for night(IR) sights.
RPK machine guns are fitted with integral folding bipods made from steel stampings. The shoulder stock is of a special shape, which facilitates the proper hold for the non-firing hand. Special versions of the RPK,made for airborne troops, had a side-folding butt stock.Such version is designated as RPKS.