The RPK (Ruchnoy Pulemyot Kalashnikova, Russian: Ручной пулемёт Калашникова or "hand-held machine gun of Kalashnikov") is a 7.62x39mm 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 7.62x39mm 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 was also manufactured in Bulgaria and Romania.
Features RPK with a 75-round drum magazine.The RPK has a new, heavier and extended barrel with an increased heat capacity. The chrome-lined barrel is permanently fixed to the receiver along with cooling ribs and cannot be replaced in the field. It is fitted with a new front sight base, gas block (lacks the 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 barrel. The barrel's muzzle is threaded, enabling the use of a blank-firing adaptor. When the blank-firing attachment is not used, the threading is protected by a thread protector cap from the AK. The barrel is pinned to the receiver in a modified trunnion, reinforced by ribbing, and is slightly wider than the trunnion used in the AKM. Symmetrical bulges on both sides of the barrel chamber ensure proper fit inside the receiver.
Like the AK-47 on which this weapon is based, the RPK and its variants such as the RPKS have a legendary reputation for their ruggedness and reliability, like many other Kalashnikov weapons.
The RPK uses a different recoil mechanism as compared to the AKM, which consists of a rear spring guide rod from the AK, and a new forward flat guide rod and coil spring.
The weapon's sights are graduated for ranges of 100 to 1,000 m in 100 m increments and the rear sight leaf has an adjustable notch.
Supplied with the RPK are: spare magazines, a cleaning rod, cleaning kit (stored in a hollowed compartment in the buttstock), a sling, oil bottle and magazine pouches (a single-pocket pouch for a drum magazine or a 4-pocket pouch for box magazines).
An RPK with a side-folding wooden stock was intended primarily for the air assault infantry. The former Soviet Union issued the RPK mainly to motorised units. Changes to the design of the RPKS are limited only to the shoulder stock mounting, at the rear of the receiver. It uses a trunnion riveted to both receiver walls that has a socket and tang, allowing the stock to hinge on a pivot pin. The trunnion has a cut-out on the right side designed to engage the stock catch and lock it in place when folded. The wooden stock is mounted in a pivoting hull, which contains a catch that secures the buttstock in the extended position. The rear sling loop was moved from the left side of the stock body to the right side of the stock frame.
Comparison of the AK-74 (top) and RPK-74 (bottom).Introduced in 1974 together with the AK-74 assault rifle and chambered for the new 5.45x39mm high-velocity cartridge. The RPK-74 derives from the AK-74 rifle, with modifications that mirror those made to the AKM to create the RPK. The RPK-74 also uses a longer and heavier chrome-plated barrel, which has a new gas block with a gas channel at a 90° angle to the bore axis, and a ring for the cleaning rod. The RPK-74 was also equipped with a folding bipod and a different front sight tower. The muzzle is threaded for a flash suppressor or blank-firing device.
The rear stock trunnion was strengthened and the magazine well was reinforced with steel inserts.
Additionally, the RPK-74 has a modified return mechanism compared to the AK-74, which uses a new type of metal spring guide rod and recoil spring. The rear sight assembly, forward handguard and receiver dust cover were all retained from the RPK.
The RPK-74 feeds from a 45-round steel or polymer magazine, interchangeable with magazines from the AK-74, and is designed to be charged from stripper clips.
Standard equipment includes: eight magazines, six stripper clips (15 rounds per clip), a speedloader guide, cleaning rod, cleaning kit, sling, oil bottle and two magazine pouches. Some variants do not come with the cleaning kit option.
It is in widespread use by member states of the former Soviet Union, as well as Bulgaria.
The RPKS-74 is the paratrooper model of the RPK-74, equipped with a wooden folding stock from the RPKS.
The RPK family of light machine guns is also available in a night fighting configuration. These weapons are designated RPKN, RPKSN, RPK-74N, and RPKS-74N. They have a side rail mounting on the left side of the receiver that accepts a NSP-3, NSPU, or NSPUM night vision sight.
An improved variant known as the RPK-74M was developed that includes a polymer foregrip, pistol grip and side-folding stock as well as a side rail for mounting optics. An export variant chambered in 5.56x45mm NATO was also introduced, designated the RPK-201. Also for export is the RPKM chambered in 7.62x39mm; it uses the same polymer furniture as the RPK-74M variant. A series of semi-automatic rifles based on the RPK receiver are manufactured by the "Molot" factory in Russia, these are known as the Vepr and Vepr 2. They are offered in several chamberings, including: .223 Remington, 7.62x39mm and .308 Winchester. They are intended mainly for the civilian market.