RPD machine gun

History

Work on the weapon commenced in 1943. Three prominent Soviet engineers were asked to submit their own designs: Vasily Degtyaryov, Sergei Simonov and Alexei Sudayev. Among the completed prototypes prepared for evaluation, the Degtyaryov design proved superior and was accepted into service with the Soviet armed forces as the 7.62 mm Ручной Пулемёт Дегтярёва, PПД (RPD, Ruchnoy Pulemyot Degtyaryova or "Degtyaryov light machine gun") model 1944. Although the RPD was ready for mass production during the final stages of World War II, large scale delivery of the weapon did not begin until 1953. During the Vietnam War, the RPD served the Vietcong as their standard light machine gun.

After the introduction of the Kalashnikov-pattern support weapons, such as the RPK and PK machine guns in the 1960s, the RPD was withdrawn from most first-tier units of the former Warsaw Pact. However, the RPD remains in active service in many African and Asian nations. Apart from the former Soviet Union, the weapon was manufactured in China (as the Type 56 LMG), Egypt, North Korea (Type 62) and, since 1956, Poland.

Operating mechanism

The RPD is an automatic weapon using a gas-operated long stroke piston system and a locking system recycled from previous Degtyaryov small arms, consisting of a pair of hinged flaps set in recesses on each side of the receiver. The movement of these flaps and the resulting locking and unlocking action is controlled by carefully angled surfaces on the bolt carrier assembly. The weapon fires from an open bolt.

Features

The RPD is hammer fired from an open bolt, the hammer forming part of the rear of the bolt carrier (which is connected to the gas piston), which continues moving forward for a short distance after the round is chambered and the bolt locked, the hammer face then striking the rear of the free floating firing pin which passes through the length of the bolt. Locking occurs by means of lateral flaps located along the sides of the bolt, which are forced outwards (by the angled sides of the hammer) into recesses cut into the receiver body, after which firing occurs when the face of the hammer strikes the rear of the firing pin; the mechanism is simple, rugged and reliable, It features a trigger mechanism that is limited to fully automatic fire only. The bolt is equipped with a spring-loaded casing extraction system and a fixed insert inside the receiver housing which passes between the feed horns of the bolt serves as the ejector. Spent cartridge casings are ejected downward through an opening in the bolt carrier and receiver. The RPD has a manually operated lever-type safety mechanism that secures the weapon against accidental firing by blocking the bolt catch when engaged. Unlike Degtyarov's earlier firearm patents, the RPD's return spring is located inside the butt. Like many other rugged Russian-made firearms, the chamber and bore are chrome-lined, greatly decreasing the risk of corrosion and jamming.

The weapon has a non-removable barrel with a 3-position gas adjustment valve used to control the performance of the gas system. It is also equipped with a folding integral bipod, wooden shoulder stock, foregrip and pistol grip. The firearm strips down into the following major groups: the receiver and barrel, bolt, bolt carrier, feed tray and feed cover, the recoil mechanism and the trigger group and stock.

Feeding

The machine gun feeds from the left side from a segmented, open-link metallic non-disintegrating belt (each segment holds 50-rounds). Two combined belts (linked by cartridge), containing a total of 100 rounds, are stored in a metal container resembling a drum that is attached to the base of the receiver. Instead of the drum, the gun can be fed by a loose belt, which can, if required, have more than 100 rounds. The feed system is operated by a roller connected to the reciprocating bolt carrier assembly and the belt is pulled during the rearward motion of the bolt carrier. The noteworthy flaw in the drum magazine's design is its unreliability in dirty conditions; it can become clogged with filth and other natural elements if they enter the magazine.

Sights

The RPD is equipped with a set of open-type iron sights. These consist of a front post (adjustable for windage and elevation) and a notched rear sight mounted on a tangent with a sliding elevation adjustment knob and marked with range indicators from 100 to 1,000 m (graduated every 100 m). A number of machine guns were fitted with a side rail (attached to the left side of the receiver) on which a NSP-2 night vision sight could be mounted.

Accessories

Standard accessories supplied with the weapon include an ammunition container, extra belts, a cleaning rod (carried on the left side of the receiver), cleaning kit (stowed in a compartment inside the stock), sling and pouches for the ammunition drums. (Although not designed for such a position, an RPD is capable of being fired from the hip by utilizing the sling to hang the gun over the user's shoulder).

Variants

During its service life, the weapon was modernized several times. Initially, the gas block was modified as was the rear sight, where the windage adjustment knob for the rear sight was moved to the left side of the notch. Later, the RPD was modified with a non-reciprocating cocking mechanism with a folding charging handle (replacing the fixed charging handle connected to the bolt carrier) that does not move during firing. The feed port received a dust cover, which when open, serves as a feeding ramp for the ammunition belt. This version of the light machine gun was produced mainly in China and Poland. A further modified variant (sometimes referred to as the RPDM) includes an extended gas cylinder and a recoil buffer mechanism in the stock. Late production RPD variants also had the fixed drum attachment removed (instead, the ammunition container was "hung" from the feed port cover) and feature a folding cleaning rod, that is stored in the weapon's butt (in the Chinese Type 56-1 variant).

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