There are actually eight forms of ammunition issued to be used during the M2 Browning .50 caliber machine gun, with the information of the various rounds coloration-coded to point their sort; these contain: Machine Gun Blowback Techniques A blowback system is one thing like a recoil method, except that the https://machguns.com/product/american-180-tuned-by-val-cooper-excellent-w-extras-b01694/