Silencer (firearms)

A silencer, also known as a sound suppressor, suppressor, or sound moderator, is a muzzle device that suppresses the blast created when a gun (firearm or airgun) is discharged, thereby reducing the acoustic intensity of the muzzle report (sound of a gunshot) and jump, by modulating the speed and pressure of the propellant gas released from the muzzle. Like other muzzle devices, a silencer can be a detachable accessory mounted to the muzzle, or an integral part of the barrel.

A typical silencer is a metallic (usually stainless steel or titanium) cylinder containing numerous internal sound baffles, with a hollow bore to allow the bullet to exit normally. During firing, the bullet passes through the bore with little hindrance, but most of the expanding gas ejecta behind it is redirected through a longer and convoluted escape path created by the baffles, prolonging the release time. This slows down the gas and dissipates its kinetic energy into a larger surface area, reducing the blast intensity, thus lowering the loudness.^[1]

Silencers can also reduce the recoil during shooting, but unlike a muzzle brake or a recoil compensator, which reduce recoil by vectoring the muzzle blast sideways, silencers release almost all the gases towards the front. However, the internal baffles significantly prolong the time of the gas release and thereby decrease the rearward thrust generated — as for the same impulse, force is inversely proportional to time. The weight of the silencer itself and the leverage of its mounting location (at the far front end of the barrel) will also help counter muzzle rise.

Because the internal baffles will slow and cool the released gas and contain gunpowder that is still burning upon exit from the muzzle, silencers also reduce or even eliminate the muzzle flash. This is different from a flash suppressor, which reduces the amount of flash by dispersing burning gases that are already released outside the muzzle, without necessarily reducing sound or recoil. A flash hider, or muzzle shroud, in contrast, conceals visible flashes by screening them from the direct line of sight, rather than reducing the intensity of the flash.