Prior to the PK, the Soviet Union had two main machine guns, the SG-43, and the DPM. The SG-43 was very bulky and heavy, and required at least two men to carry the gun, ammunition, and mount.

Marines with Task Force Southwest fire PK general-purpose machine guns during foreign weapons familiarization training at Camp Lejeune, N.C., Jan. 17. (U.S. Marine Corps photo by Sgt. Lucas Hopkins) ...

Prior to the PK, the Soviet Union had two main machine guns, the SG-43, and the DPM. The SG-43 was very bulky and heavy, and required at least two men to carry the gun, ammunition, and mount.