.50 BMG_12,7 x 99 mm NATO

.50 BMG (Browning machine gun), caliber 12.7 x 99 mm. American ammunition for M2 Browning large-calibre machine guns mounted on aircraft or vehicles used since 1921. Under the Lend-Lease Act, the Soviets received, among others, American aircraft Bell P-39 Airacobra, Bell P-63 Kingcobra, Douglas A-20, where M2 Browning machine guns were also mounted. Thus, it is very likely that the recovered cartridges came from these originally American aircraft in Soviet service. Production of "TW 4" and "42 TW" - Twin Cities Ordnance Plant, Minneapolis, Minnesota, USA.

TW – Twin Cities Ordnance Plant was an ammunition factory established in 1941. It was one of six government-owned, contractor-operated (GOCO) factories operated by private contractors. These factories were established for purposes of the Lend-Lease Act prior to U.S. involvement in World War II. During the war, the factory produced over 4 billion rounds of .30, .45, and .50 caliber ammunition. After environmental scandals in the 1980s, it was finally closed in 1993.