The MG 81 machine gun was based on the MG 34. The MG 81 was used on aircraft. It got its ammunition from a belt and fired 7.9 mm rounds. There were never enough MG 34s made to make its users happpy. Even though the MG 81 was much better than the MG 15 and MG 17 used before it, they were still used until the end of the war.