What is a “silencer”? Properly speaking, the devices are called “suppressors” or “moderators,” because guns that use them are still very loud, as will be detailed below. A sound suppressor is based on the principle you can see in a bathtub drain. Because water swirls when it goes down the drain, the rate of water flow is less than if the water just went straight down. The same principle can be applied to a gas. In a firearm, the bullet is propelled through the barrel and out the muzzle by expanding gas from burning gunpowder. As the gas exits the muzzle, it makes a very loud noise. If gas swirls on the way out, it exits more slowly. The slower exit reduces the noise of the gunshot.
Thus, a suppressor is a simple canister attached to the gun muzzle. Inside the canister are baffles, which make the gas swirl, producing less sound.
The first sound moderator came to market in 1909, under the name “Maxim Silencer.” The name was marketing hyperbole, like calling a flannel shirt an “Arctic coat.” The inventor, Hiram Percy Maxim, also applied his noise-moderating system to automobile mufflers and other machines whose gas emissions create noise. Today, the company Maxim Silencers does not make firearms silencers, but it does produce noise reducers for many other applications.
by David Kopel
