Goryunov MG 7.62mm

The SG-43 Goryunov [ Russian: Смонтированный пулемет системы Горюнова (Smontirovannyy pulemet sistemi Goryunova > "Mounted machinegun, Goryunov design")] was a Soviet medium machine gun that was introduced during the Second World War. It was chambered for the 7.62×54mmR cartridge, and was introduced in 1943 as a replacement for the older M1910 Maxim machine guns. It was mounted on wheeled mounts, tripods and armored vehicles.
The SG-43 used a tilting breechblock, moving sideways and locking into the side of the receiver. The feed is not straightforward, as the gun fires the 7.62×54mmR round, and this has to be withdrawn rearwards from the belt before ramming into the breech. The reciprocating motion is achieved by using two claws to pull the round from the belt, and then an arm pushes the round into the cartridge guide ready for the bolt to carry it to the breech. Despite this complication, the SG-43 was remarkably reliable and feed jams were apparently few.
More:https://en.wikipedia.org/wiki/SG-43_Goryunov