Gun Silencer: How Does A Small Metal Pipe On The Barrel Silence A Gun?

Covert operatives and spies, especially those they show in movies, are always equipped with a handful of important tools that they carry everywhere. A gun, as you might expect, is the single most important part of their ‘go-bags’, but many agents and spies, if not all, like to carry another accessory that ensures privacy. In the covert business, not making an auditory signature when you fire a weapon is important, so gun silencers are popular add-ons for certain gun users.

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You have certainly seen these in plenty of movies, but now let’s look at how a gun silencer actually works.

What is a Gun Suppressor?

gun silencer rifle Everyone already knows that there is a loud bang when a gun is fired (For more information, read Why Do Guns Make So Much Noise?), but that isn’t always desirable in certain situations. A suppressor (also referred to as gun silencer or sound moderator) is a device that attaches to the end of the barrel of a firearm and reduces the amount of visible muzzle flash and sound produced by firing the weapon.

pistol silencer

Credit: barbulat/Fotolia

It’s important to note that it does not entirely mute the sound of the firearm; that cannot happen under regular conditions. What it does is significantly reduce the sound when a bullet is fired, and therefore you hear quite a softer sound rather than a loud bang.

How Does a Gun Suppressor Work?

A suppressor, typically cylindrical in shape, is usually a hollow metal tube made of steel, titanium or aluminum. It consists of expansion chambers, which are actually the functional part of the accessory.

To fire a bullet, you just have to pull the trigger, but a lot goes on inside the gun to make the bullet speed at your target at such a high speed. When you pull the trigger, gunpowder is ignited behind the bullet, which creates a high-pressure pulse of hot gas. This is the extreme pressure that makes the bullet fly down the barrel at such a high speed. The moment the bullet exits the barrel, the high-pressure gas pulse expands out of the muzzle, producing a loud noise.

But what if you somehow allow the gas to expand within the barrel?

This is precisely what a suppressor does. It attaches to the barrel, adding a few inches of length to the end. Its volume is also huge; roughly 30 times more voluminous than the barrel. Furthermore, it has expansion chambers, which allow the high-pressure gas to expand through the series of chambers. As a result, the gas that comes out of the end of the suppressor is considerably expanded and has a significantly lower pressure. For that reason, the sound is suppressed, so the gunshot is much softer.

james bond silencer

Gun suppressors are a common sight in spy movies

However, there is still some release of pressurized gas; therefore, the firing of a gun is not absolutely muted, even when using a suppressor. Also, note that the boom you hear when a bullet is fired is not the only audible sound associated with firing a gun. There is also the sonic boom of the bullet, which cannot be suppressed by a suppressor. Still, a gun suppressor is an immensely helpful accessory, especially for covert field operations. Now, the next time you see 007 carrying a revolver with a rather long accessory at the end, you’ll know he’s preparing for some silent shooting!

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About the Author

Ashish is a Science graduate (Bachelor of Science) from Punjabi University (India). He spearheads the content and editorial wing of ScienceABC and manages its official Youtube channel. He’s a Harry Potter fan and tries, in vain, to use spells and charms (Accio! [insert object name]) in real life to get things done. He totally gets why JRR Tolkien would create, from scratch, a language spoken by elves, and tries to bring the same passion in everything he does. A big admirer of Richard Feynman and Nikola Tesla, he obsesses over how thoroughly science dictates every aspect of life… in this universe, at least.

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