marcus who:

A silencer acts in the same manner as a tapered turd. By being tapered the turd does not allow your cheeks to come back together too quickly and cause a slapping sound every time you expell a complete turd.

In an airgun, the pressurized air splits the atmosphere and causes a vacumn to be formed behind the rapidly expelled air from the gun. Since mother nature abhors a vacumn, the atmosphere rushes in to fill the vacumn, and the sound you hear is the clapping of the atmosphere filling the vacumn and hitting itself.

A silencer slows down the expulsion of the air after the pellet has left the barrel and thereby reduces the size of the vacumn, and the speed necessary for the atmosphere to refill the void.

Bountyhunter

P.S. I am looking for a full copy of Paladin Presses "Hitman" on the web complete with all pictures. I have found a site with just the text, but I would like the whole thing. It's an academic interest as I know most of its techniques from other books.