Made from an actual once fired .50 cartridge.
The .50 Browning Machine Gun (.50 BMG) or 12.7×99mm NATO is a cartridge developed for the Browning .50 caliber machine gun in the late 1910s. Entering service officially in 1921, the round is based on a greatly scaled-up .30-06 cartridge. The cartridge itself has been made in many variants: multiple generations of regular ball, tracer, armor piercing, incendiary, and saboted sub-caliber rounds. The rounds intended for machine guns are linked using metallic links.The .50 BMG cartridge is also used in long-range target and sniper rifles, as well as other .50 caliber machine guns. The use in single-shot and semi-automatic rifles has resulted in many specialized match-grade rounds not used in .50 caliber machine guns.