Yep......U.S. .50/12.7mm Nato BMG Cartridge produced by the Lake City Ammunition Plant in 1991. Fired from the Browning M2, M3, ANM2 Machine Gun. Used by U.S. Forces since its introduction in 1918 and still very much in use today. Used on many armored vehicles, tanks, and Aircraft of WWII. In use in the Middle East right now. Much military training went on along the East Coast of the U.S. at various locations.
Your example was made in 1991.
Lake City Army Ammunition Plant located at Independence, Missouri, in Jackson County, is the largest small-arms (5.56 - 20 mm) manufacturing plant in the world. With the exception of the five year period between the end of World War II and the beginning of the Korean conflict, this government-owned, contractor-operated facility has been in continuous production since October 1941.
TiredIron