Due to short barrel, the vehicle-15 SMGs suffered from a loud and bright muzzle blast, and several muzzle equipment had been created to cut back this. The SMGs were being in the beginning fitted with the common M16 rifle's "duckbill" or 3-prong flash hiders, which didn't relieve the issue. In September 1966, Colt formulated a 3.five-inch (89 mm) p