This threading allows various muzzle devices to be attached ... Shown here is an A2 flash hider, designed specifically for M16, M4 and AR-15 type rifles. When fitted with typical 16" barrels ...

A 9mm handgun, the most popular, has muzzle velocity of 1,200 feet per second. Meanwhile, an AR-15 5.56 caliber weapon clocks in at 3,251 feet per second. That would be almost three times faster ...