Quad 50 - The M-55 Quad 50, known as " Whispering Death" had four 50 caliber machine guns mounted on a deuce and a half  truck. It had a combined 1,500 rounds per minute rate of fire, blanketing an area up to half a mile away.  It was frightening to hear it firing.  I can't imagine what it must be like to be on the receiving end. They were used mainly for convoy support.