How does a silencer work?

Question

It fascinates me because you attach this thing to your gun and the bullets are very very silent. Plz explain i really wanna know.

Answer 1

A silencer works much like a car muffler.  It provides a space for the gun powder gas to expand and cool before it exits.  Most modern silencers have cone shaped baffles that interfere with the gun powder gas flow through the silencer.  This turbulence delays the exit into the atmosphere and helps reduce noise more.  

While a firearm is very noisy, about 130 to 160 decibels, a silencer will reduce the noise by about 20 to 30 decibels.  While a suppressed firearm is still at least 110 decibels, this impulse noise is very short lived and does not appear to be very loud.  If you have the chance to listen to the difference between a suppressed and unsuppressed rifle in person, the change in noise level is very dramatic.  

A silencer needs volume to reduce noise.  The longer and wider the better; although most shooters do not want very large can hanging on the end of their rifle or pistol.  Alignment is also important as most silencers only have about 1/16th of an inch clearance between the bullet and the baffles.  Mount a silencer crooked on the barrel and the bullet will hit the internals and ruin accuracy at best, or destroy the silencer at worst.  Silencers for recoil operated semi-auto pistols frequently use a linear de-coupler (recoil enhancer) so that the slide will function properly with the extra weight on the barrel.

Silencers only reduce muzzle blast noise.  They do nothing for bullet flight noise, especially the small sonic boom created by bullet moving faster than 1100 feet per second.  They also do nothing for action noise; the noise made by the bolt moving back and forth on machine guns and semi-automatic firearms.  They also work poorly on most blow-back pistols and revolvers due to the gap between the cylinder and barrel.  Nagant revolvers and others made with a small or sealed gap work well with silencers.  

Silencers are legal in most states.  ATF approval to make or buy them is routine.

Answer 2

It is amazing that anything is able to silence a gun, but gun silencers actually work on a very simple principle.

Imagine a balloon. If you pop a balloon with a pin, it will make a loud noise. But if you were to untie the end of the balloon and let the air out slowly, you could pop it making very little noise. That is the basic idea behind a gun silencer.

To fire a bullet from a gun, gunpowder is ignited behind the bullet. The gunpowder creates a high-pressure pulse of hot gas. The pressure of the gas forces the bullet down the barrel of the gun. When the bullet exits the end of the barrel, it is like uncorking a bottle. The pressure behind the bullet is immense, however -- on the order of 3,000 pounds per square inch (psi) -- so the POP that the gun makes as it is uncorked is extremely loud.

A silencer screws on to the end of the barrel and has a huge volume compared to the barrel (20 or 30 times greater). With the silencer in place, the pressurized gas behind the bullet has a big space to expand into. So the pressure of the hot gas falls significantly. When the bullet finally exits through the hole in the silencer, the pressure being uncorked is much, much lower -- perhaps 60 psi. Therefore, the sound of the gun firing is much softer.

Answer 3

Everyone already explained the story behind the silencer... So I'm not gonna bother.

Part 2... What kind of round(bullet) are you firing. A subsonic round plus a silencer will significantly reduces its report(sound or whatever you like to call it)...