Developed as a portable, squad-level light machine gun, the RPD ("Ruchnoy Pulemot Degtyaryova" - "Hand-Held Machine Gun of Degtyaryov") was a further evolution of the storied DP line introduced in 1928 by Vasily Degtyaryov. The DP was appropriately modernized through the DPM and RP-46 initiatives but these were chambered for the full-power 7.62x54mmR Russian rifle cartridge. In the new design, this shifted to the smaller 7.62x39mm cartridge which promised more control. Work on what would become the RPD began during World War 2 (1939-1945) in 1943 and some three competing designs were offered for review to Soviet authorities for possible acceptance. The Degtyaryov submission was, at its core, nothing more than a down-sized DP. It was eventually accepted in 1944 as the "RPD" though only in limited pre-production form by the end of the war in 1945.
Delays eventually meant that the RPD was not issued on a large scale until 1953 and it established itself as the standard light machine gun / squad support weapon of the Soviet Army in time, intended to be paired with infantry squads already equipped with the famous Kalashnikov AK-47 assault rifle for extensive voluminous fire. The RPD utilized an action centered on a conventional gas-operated piston system. The gun weighed 16.3lbs and featured an overall length of 41 inches with a barrel 20.5 inches in length. Unlike the DP and its variants, the barrel of the RPD was not changeable. Rate-of-fire approached 750 rounds per minute with a muzzle velocity rated at 2,400 feet per second. Effective range through the included fore and aft iron sights was up to 1,000 meters.
The RPD showcased a rectangular receiver containing the charging handle, ejection port, aft sighting device, trigger unit and all associated internal components. A shapely wooden stock was affixed for a butt and the pistol grip was also of wood. A unique handguard was seated just ahead of the receiver and at the base of the barrel and gas cylinder. The cylinder was mounted under the barrel - unlike Kalashnikov weapons that feature this over the barrel. The barrel was capped by a forward sighting device and saw a folding bipod clamped at this area. In this fashion, the weapon could be fired from the shoulder as a typical assault weapon or seated on its bipod for support fire/suppression of enemy positions.
Chambered for the 7.62x39mm rifle cartridge, the RPD became the first Soviet automatic weapon to feature this round. It was of a rimless, bottleneck design and saw extensive production throughout the Cold War - indeed its use still continues even today (2014). 100-round belts were seated within a drum magazine clipped under the receiver. A special mechanism was used internally to lift and feed the belt into the action.
The RPD was appropriately altered throughout its service life. Its piston and cocking handle were both changed within time and as operational service dictated. The gas cylinder was lengthened while a recoil absorber was added within the buttstock for more stable firing. A cleaning rod was issued and housed in the buttstock while a magazine cover was installed to prevent stoppages from dirt and debris. Despite the additions and modifications, the feed mechanism was never a truly sound effort for it was noticeably lacking in the required power. Additionally, the weapon's action was limited to full-automatic fire only which, coupled with the weapon's light weight, proved somewhat problematic for accuracy. Add to that the lack of a changeable barrel and it was up to the operator to ensure that the barrel did not overheat. A sustained rate-of-fire of 100 rounds in a minute was the absolute stated limit.
Production of the weapon spanned from 1944 to 1960 though usage extended well beyond that window. Operators were numerous and included Afghanistan, China, Egypt, Finland, East Germany, Hungary, Indonesia, Iraq, Laos, Libya, North Korea, Pakistan, Romania, Sudan, Syria, Thailand, Vietnam and Yemen among others (see operators listing). The Chinese locally-produced the weapon as the "Type 56" under the NORINCO brand label. While the Soviets succeeded the RPD with the RPK line, the RPD still continues in service with select forces today (December 2013). The weapon's combat history includes World War 2, the Korean War, the Vietnam War, the Cambodian Civil War, the Iran-Iraq War, the 1991 Gulf War, the 2001 Invasion of Afghanistan, the 2003 Iraq War, the Libyan Civil War and the Syrian Civil War. There have also been numerous regional conflicts utilizing the type.