50 Caliber Machine Gun ... is used to feed the ammunition into the weapon. This gun is has a back plate with spade grips, trigger, and bolt latch release. This gun may be mounted on ground ...

50 caliber Browning Machine Gun cartridge ... The effort resulted in a bolt-action rifle known as the M30-Tactical System ...

50 caliber sniper rifle ... officials said. The bolt-action precision rifle, meanwhile, is one part of a system that includes ...