Also called the Light Fifty (due to its chambering of the .50 BMG 12.7×99mm NATO cartridge), [2][3] the weapon is classified in three variants: the original M82A1 (and M82A3) models, the bullpup M82A2 model, and the Barrett M107A1, with an attached muzzle brake (designed to accept a suppressor, and made out of titanium instead of steel).