Silencers and Mufflers

[Cap'n Refsmmat]

Two things:

1. How does a silencer (on a gun) work?
   
2. How does a muffler (on a car) work?
   

[bloodhound]

this is taken from http://people.howstuffworks.com/question112.htm

 

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.

[Cap'n Refsmmat]

Thank you.

[YT2095]

and it`s not worth using one with anything other than subsonic rounds

[5614]

although if you wanted to kill your neighbour, without your parents/wife/whoever lives with you hearing, i would advise using a silencer, and a muffler for a car works in a similar way, i think, i heard the explanation although i think there were other factors, i cant remember them though.

[swansont]

As far as silencers, go, read the silencers bit on the Insultingly Stupid Movie Physics page. Scroll down to "The Sound of Movies"

 

 

(You may want to pause and read "The Attractive Force of Glass" The last bit about the shooter recoiling too was added just a few days after I suggested it. Coincidence? )

[drz]

mufflers are pretty interesting. If you have a spare one laying around, and perhaps a sawz all (saw zaw) cut it open and you will understand instantly.

 

Anyhow, there is an inlet and outlet. The exhuast rushing in is hits walls placed within the muffler, some have screens, but the walls basicaly cause the exhaust gas to cycle around inside the muffler, then exiting at a slower rate.

 

This slowing of the exhaust actually hinders engine performance, which is why more high performance mufflers, free flowing exhaust, is louder. It has less walls to slow down the exhaust, basically.

[YT2095]

a car muffler wont work with a gun properly, you`ll maybe get a few db drop at best.

they have to be "tuned" to resonance and also it`s round type specific!

 

the idea of using a plastic coke bottle a pillow or a tube full of washers (as seen on TV) is plain ridiculous! actualy the pillow idea`s the most effective of the lot, but not at all good.

 

and the little tiny silencers you see on these sub-machineguns and large riffles are a load of crap too (again seen in the movies). to get effective silencing for these type of weapons the silencer is actualy as big as the gun in most cases! and it`s still quite loud!

also, for a fully automatic weapon, the silencer needs cleaning and COOLING! after a few clips. certainly not what they show you in the movies or on TV

[coquina]

I think the silencer also reduces the power of the bullet, so you have to be close -