The DShK (Degtyaryova-Shpagina Krupnokaliberny) was a heavy machine gun and was first developed in 1933. The early models were only built in small numbers and these were fed by a thirty round drum. Modifications were done to allow for a belt feed system and these were issued in 1938. It fired a heavy 12.7mm round and this allowed it to function as a ground weapon and as an anti-aircraft gun. In the ground role it was mounted on a wheeled carriage and provided with a gun shield.