1968 edition. A silencer, also known as a sound suppressor, suppressor or sound moderator, is a muzzle device that reduces the acoustic intensity of the muzzle report (sound of a gunshot) and the recoil, when a gun (firearm or air gun) is discharged, by modulating the speed and pressure of the propellant gas from the muzzle and hence suppressing the muzzle blast. Like other muzzle devices, a silencer can be a detachable accessory mounted separately onto the muzzle, or an integral part of the barrel. ; Report R-1896; B&W Illustrations; 8.4 X 5.4 X 0.7 inches; 205 pages View More...