Pistols and silencers

[Freak]

How does a silencer work on a pistol?

[Hippy]

The bang you hear when a gun discharges is due to the rapidly expanding gasses expelled from the gun barrel, and that propels the bullet or load of shot. The bullet or shot travels at subsonic speed and therefore makes no sound, however the escaping gas is a lot faster. Think of a champagne cork popping from the bottle. The cork is never supersonic but the pop caused by the first release of fizz certaily is. You can make a similar sound from popping your finger from your mouth with a little pressure behind.

 

The gun's silencer seeks to absorb the energy of the gasses and slow them down as soon as they emerge from the gun barrel. The bullet carries on through a continuation of the barrel that is pierced with slots allowing the gas behind the bullet to expand relatively slowly into a larger chamber fitted with internal baffles and venting the gas slowly and relatively silently.

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[Clanad]

While the discussion of how the silencer works is, essentially, correct, the statement about bullets being subsonic is not. In air, the speed of sound is approximately 1100 feet per second. Typical bullet velocities for rifles, on the other hand, are on the order of thousands of feet per second. This means that rifle bullets travel faster than the speed of sound and will cause a sonic tearing as they travel through the air. This has important complications for silencers because it means that to get a firearm to be sufficiently quiet, you must have bullets that travel at a velocity less than the speed of sound. As a result, silenced rifles are largely ineffective at long range because they experience more drop...

[Hippy]

Yup, Clanad, you are right there about muzzle velocity and rifles. However, Freak asked about pistols which typically have lower muzzle velocities than rifles, and as you say the bullet has to emerge at under sonic speed to be effectively "silenced".

 

What a pity that you go to all that trouble to have a pristine state of the art weapon primed to capacity, only to experience droop when it comes to the bang! Now where have I come across that before? Hmm ...

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[slimfandango]

when you were last having sex?