RPD machine gun

The RPD is a Soviet light machine gun that fires the 7.62×39mm M43 intermediate cartridge. It was designed by Vasily Degtyaryov to replace the earlier DP machine gun, which used the larger 7.62×54mmR round. The RPD is considered a forerunner of modern squad automatic weapons. Development began in 1943, with three prominent Soviet engineers—Vasily Degtyaryov, Sergei Simonov, and Alexei Sudayev—each submitting a design. After evaluation, Degtyaryov’s prototype was chosen and adopted by the Soviet armed forces as the 7.62 mm RPD model 1944. Although the RPD was ready for mass production during the final stages of World War II, it was adopted in 1948 and large scale delivery of the machine gun did not begin until 1953. During the Vietnam War, the RPD and its Chinese copy, the Type 56, were the standard light machine guns for the Viet Cong and the People’s Army of Vietnam. After the introduction of the Kalashnikov RPK and PK machine guns in the 1960s, the RPD was phased out of most front-line units in the former Warsaw Pact. However, it remains in active service in many African and Asian countries. The RPD is gas-operated with a long-stroke piston system and fires from an open bolt. Its locking mechanism, borrowed from earlier Degtyaryov designs, uses a pair of hinged flaps that fit into recesses on each side of the receiver. Angled surfaces on the bolt carrier control the flaps’ movement for locking and unlocking. The hammer is part of the rear of the bolt carrier, which continues forward after a round is chambered and the bolt locks, striking the rear of a free-floating firing pin that runs through the bolt. Locking happens when the flaps are forced outward by the hammer’s angled sides into receiver recesses; then the hammer hits the firing pin. This system is simple, rugged, and reliable. The trigger mechanism allows only fully automatic fire. The bolt has a spring-loaded casing extractor, and a fixed insert in the receiver acts as the ejector, passing between the bolt’s feed horns. Spent casings are ejected downward through openings in the bolt carrier and receiver. A manual lever-type safety blocks the bolt catch when engaged. Unlike earlier Degtyaryov designs, the return spring is inside the buttstock. The chamber and bore are chrome-lined to resist corrosion and jamming. The barrel is non-removable and has a three-position gas adjustment valve.