carbine with belt-fed upper receiver that convert ar-15 or m16 from a standard, magazine rifle to light machine gun. on a

223 556mm american ammunition ar-15 arms army assault automatic background belt belt-fed beltfed black carbine cartridges chain convert defense fire firearm forces gun illegal isolate isolated law legal light link m16 machin machine magazine marines military modern nato receiver rifle round shot shotgun sight soldier standard target upper usa usgi violence war weapon white