Due to short barrel, the CAR-fifteen SMGs endured from the loud and bright muzzle blast, and many muzzle gadgets were designed to lessen this. The SMGs have been at first fitted with the common M16 rifle's "duckbill" or a few-prong flash hiders, which did not ease the trouble. In September 1966, Colt made a 3.five-inch (89 mm) prolonged moderator