Written by Linda Alexander
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Gun silencers suppress the sound a gun makes, but they do not eliminate it. A better word would be "suppressor" or "moderator." They are widely used by hunters to reduce noise pollution. The sound a gun makes with a silencer is more like a car door being slammed than the loud pop we are used to hearing.

When a firearm is discharged, much of the gas from the gunpowder explosion has dissipated, but it is not completely gone. The gas expands when it leaves the barrel, causing a wave of pressure in the air, which we hear as a gang. Silencers change the rate at which this gas expands, making the shot sound quieter.

The way silencers work has been compared to releasing air from balloons. When you pop a balloon, it makes a loud sound as the air expands. If you untie the end of the balloon and let the air out slowly, it is not as noisy.

Silencers and Supersonic Ammunition

In order for suppressors to work, they must be used with bullets that travel slower than the speed of sound. They will not work with supersonic bullets. When silencers are used with ammunition that travels at less than the speed of sound, the noise is greatly reduced.

If you use a suppressor with a supersonic bullet, it cannot reduce the noise, but it can change the way it sounds. The noise of the discharge is made up of the expansion of the gases as well as the supersonic crack of the bullet. The suppressor controls the rate of expansion of the gases, so it can alter the sound even though it will be just as loud.

The silencers seen in Hollywood movies are not true to life. In real life, suppressors are much larger than the ones shown in movies. The noise of the discharge is also different; movies tend to make the guns completely silent when in actuality there is still some sound left.

Construction of Silencers

Typically, a silencer consists of a metal cylinder divided into two sections fixed to the gun barrel. The first section, about a third of the silencer's length, is an expansion chamber for dissipating some of the energy of the hot gases that follow the bullet. The second section is made of a series of baffles, with a hole in the center to allow the bullet to pass through. The metal baffles slow the flow of gas from the expansion chamber, so that they are cooler and moving slower by the time they leave the silencer.

The first silencers were patented by Hiram P. Maxim, an American inventor, in 1910. They are used today primarily to reduce noise pollution and save hearing. The sound of firearms can wreak havoc on the hearing of shooters, so a silencer is a good way to reduce the damage done. Of course, before installing one on your gun, be sure to check all federal, state, and local laws, since they are illegal in many areas.

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