PK machine gun

Lore & Background

The Main Artillery Directorate of the Soviet Union adopted specification requirements for a new 7.62 mm general-purpose company and battalion-level machine gun in 1955. In 1958, a prototype by G.I. Nikitin and Yuri M. Sokolov, the Nikitin-Sokolov PN1, passed field tests, and a batch was ordered for service tests. However, the PK had flaws, the main flaw being that the machine gun did not resist water and snow very well. Water and snow had a tendency to enter the gas piston, causing the gun to fire only shot by shot after two or three rounds. The army asked Nikitin to solve this problem, but the engineer took too long. To force faster work, the Main Artillery and Missile Directorate restarted the competition in 1958. A team from the Izhevsk Mechanical Plant headed by M.T. Kalashnikov joined, despite the PN1 already being chosen by the army. Their prototype was based on the gas-operated rotary-bolt design of Kalashnikov-pattern arms. Both prototypes underwent service tests in late 1960. The Main Missiles and Artillery Directorate and the Ministry of the Defence Industry preferred the Kalashnikov design. The PK could resist water perfectly and was easier to maintain and manufacture, reusing the same ammunition bands as the Maxim or SG-43, while the PN1 used a new type not yet in production. Kalashnikov claimed competitors attempted to bias the test by asking operators to lower the rate of fire due to overlapping bands during long bursts, and that the PN1's recoil was so poorly distributed that a soldier broke his cheekbone. In 1961, the Kalashnikov design was adopted and put into production at the Kovrov Mechanical Plant, using the tripod mount and ammunition belt boxes originally designed for the Nikitin-Sokolov prototype. Nikitin's and Sokolov's design was later used in the 12.7 mm NSV heavy machine gun put into production in 1971. In June 2024, it was reported that the PKZ will eventually replace the PKM in Russian military service.

Reader's Guide

The PK and its modernised PKM variant have served as the standard general-purpose machine gun of the Soviet Union and later Russia for decades, replacing the SGM and RP-46 machine guns. The design's significance lies in its adaptation of Kalashnikov's proven gas-operated rotary-bolt system to a full-power rifle cartridge, enabling reliable automatic fire in a relatively lightweight package. The PK's open bolt design improves heat management during sustained fire, reducing the risk of cook-off, and its quick-change barrels allow prolonged use. The PKM's service life is guaranteed for at least 25,000 rounds with a spare parts kit and two barrel assemblies. The weapon has been exported extensively and produced under license in several countries, such as Zastava Arms in Yugoslavia producing the M84 and M86. The most recent modification, the PKP Pecheneg, features a forced air cooling barrel with a longer barrel life of up to 10,000 rounds. A remotely controlled PKT version reportedly entered service in November 2023. The PK's feed mechanism, derived from Louis Stange's MG 39 Rh and copied in Czechoslovak machine guns, pulls rimmed cartridges from the belt and drops them into the feed way, differing from the MG 42-style forward-feed mechanism used in many NATO machine guns. The PK's continued frontline use and planned replacement by the PKZ as of June 2024 underscore its enduring role.

Did You Know?

• The PK's bolt and carrier are oriented upside down compared to the AKM, with the piston and gas system underneath the barrel.
• The PK uses a two-stage feed mechanism with preliminary extraction from a belt link due to its rimmed cartridge.
• The PK's feed mechanism is radically different from that of 7.62×51mm NATO machine guns based on the MG 42 feed mechanism.
• The PKP Pecheneg modification features a forced air cooling barrel with a barrel life of up to 10,000 rounds.