The DShK 1938 (Degtyaryova-Shpagina Krupnokaliberny, “Degtyaryov-Shpagin Large-Calibre”) became the standard Soviet heavy machine gun of WWII. It fired 12.7x108mm cartridges (the West’s M2 .50 cal fired 12.7x107mm) fed by belt or box magazine. It was frequently deployed with a two-wheeled cart and a single armor shield (similar to that used by the Maxim) as well as on a tripod for anti-aircraft. It was mounted on GAZ trucks, on late war tank cupolas (IS-2, ISU-152) in tank turrets (i.e. T-40), and other vehicles and ships.
A modernized DShK 1938/46or DShKM version appeared post war, which looked much the same. The Soviet Union , Russia, People's Republic of China, Pakistan and Romania have manufactured the DShK which has appeared throughout the world. I recall in Vietnam it was called a “.51 cal.” as it fired a slightly larger round than our M2 (the rounds were not interchangeable), and was one of the weapons our vulnerable helicopters learned to respect.