How does a gun silencer work?

Answer 1

Bound's hubby here:

Many of the answers contained herein are good answers. If you dissect an automobile muffler, there is very little conceptual difference from a firearms' silencer (or more correctly, suppressor).

The firearm's silencer contains a perforated barrel extension, that allows the propellant gases to flow into the expansion chamber formed by the barrel extension and the outer shell. Between the barrel extension and the outer shell is a medium, typically, steel wool. As the gasses flow into the expansion chamber the gases flow around/through the steel wool, cooling the gasses, and muting the crack of the shot (to a degree). Silencers will work with both sonic and subsonic ammunition ... it is that the silencer is MORE EFFECTIVE with subsonic ammunition.

What many people have neglected to state, is the silencer's effect on the external ballistics of the projectile. Typically, the bleed-off of the propellant gasses slows the velocity of the projectile, reducing both its muzzle velocity and its muzzle energy! A firearm shot with both a silencer on and off, will hit in different places, and different effects on the object being shot.

Good luck!

Answer 2

A silencer(more correctly called a suppressor)is(usually) lined with a series of perforated baffles to slow down/trap the expanding gasses from the shot. The expansion of gasses from the barrel breaking the sound barrier is the largest producer of noise in a gunshot. Remember, if you are not using subsonic ammunition, the bullet will produce a sonic boom. Silencers must be used on a closed system, such as an automatic, a single shot or bolt action weapon. They will not work on revolvers(with a few exceptions), as the movies love to show. A good silencer will reduce the noise level an amazing amount. I have stood next to someone firing a HK MP5 SD on full auto, and it sounded like a sewing machine. Most are nowhere near this quiet, though, reducing the noise level to about that of popping a baloon or paper bag. Hence the term suppressor.

Answer 3

The bang of a gun is made by the sudden change in air pressure caused when the hot gases that drive the bullet exit the muzzle.

The silencer contains a central perforated tube down which the bullet travels. The silencer is surrounded by a bigger cylinder. The hot gases following the bullet expand through the perforations in the tube and into the cylinder, so that when they reach the atmosphere, they have slowed down and the change in air pressure when the hot gases reach the air is lower. This reduces the loudness of the bang. (The bang is caused by the gases rather than the bullet itself.)

Answer 4

A silencer works much like a car's muffler. The space in the silencer and muffler both give the excaping gasses a place to expand and slow down there by reducing the noise created as it leaves the muzzle or exaust tip. Plus as someone else already advised subsonic loads make then entire device more efficient.

Answer 5

The sound is made when the pressure of the gas that is propelling the slug exits the barrel. It is at such a high pressure that it makes a loud noise. The silencer allows the gas to expand before the bullet leaves the end of the silencer. The gas is at a lower pressure therefore makes a lower sound.

Answer 6

I agree with most of what is said here, except for the part about bullets slowing down in a suppressor. This only happens when using a suppressor equipped with wipes or mesh that contacts the bullet. The only suppressor design I am aware of that uses a perforated barrel extension are the ones made for shotguns. The tube keeps the shot wad closed until it exits the suppressor.

All modern pistol and rifle suppressor designs I have seen use baffles that do not contact the bullet at all unless the suppressor is out of alignment. Ported barrels reduce bullet velocity because gas is ported out of the barrel while the bullet travels down it. Ported barrels are not barrel extensions, but part of the barrel complete with rifling.

Answer 7

Most of the answers above are correct, the only thing I'd add is that you need to use subsonic ammunition too or the sonic boom of the bullet will still be audible. How loud is the sonic boom of a bullet? When I marked targets at the 200 yard Short Siberia and the 600 yard Century ranges at Bisley I used to wear hearing protection in the target butts. It's hard to locate a gun from just the crack of the bullet though.

Answer 8

There is no such thing. There are however, suppressors. They vent gas and reduce the noise of the gun firing. Get "Firearms and Firepower" video for a excellent showing of the truth about bullet power/penetration and suppressors.

Answer 9

It silences.