Gun Suppressors: How They Work and How They’re Made

What is a suppressor?

In the most simple terms, a suppressor is essentially a muffler for a firearm. Similarly to how an automobile muffler reduces the very loud sound produced by the expanding gases of an internal combustion engine, a firearm suppressor reduces the very loud sound produced by the expanding gases of a firearm (or even an air rifle). A car’s muffler contains, redirects, and “muffles” the gases and sound waves exiting an engine, and a firearm suppressor contains, redirects, and “suppresses” the high-pressure gases and sound waves exiting the muzzle of a gun.

What are the benefits of a firearm silencer?

The first and most important benefit of a suppressor or silencer is that it greatly reduces the potential for permanent hearing loss to the firearm user and others in the area. Gunshots are extremely loud, usually over 140 decibels and up to 175 dB or more for some high-pressure cartridges.

It’s important to understand how decibels work: It’s not a linear scale. Decibels are measured and graphed logarithmically, or exponentially. Every increase of 10 dB on the decibel scale is equal to a 10-fold increase in sound pressure level. So, if 1 decibel is nearly silent, a 10 dB increase means 10 times louder, while a 20 dB increase means 100 times louder. So the difference between a “hearing safe” 115-130 dB shot from a suppressed firearm and a “not-hearing-safe” shot from an unsuppressed firearm at 140+ dB is huge. For reference, a rock concert may average between 90 and 120 dB. A jet engine at takeoff is around 140 dB.

Your hearing can be permanently damaged by a single close-range exposure to a loud noise over 140 dB, or by prolonged exposure to noises as low as 80-110 dB. Within enclosed spaces (like indoor shooting ranges or your house) the potential for damage increases. The more you shoot, the greater the potential for permanent hearing loss. Suppressors are important safety features on many firearms.

Another benefit? In some cases, suppressors can help reduce the punishing recoil of large, powerful firearms. The weight of the suppressor helps a little, but trapping that explosive gas against the internal surfaces of the suppressor can also act to reduce felt recoil, and the shocking muzzle “concussion” of an unsuppressed shot is also reduced or removed, which helps further.

Additionally, some firearms are more accurate with a good suppressor fitted. It may seem illogical or implausible, but ask anyone who has shot a lot of firearms suppressed and unsuppressed and they’ll likely tell you that some guns, with some loads, are much more accurate when using a suppressor. This may have to do with barrel harmonics, the reduction/dispersion/slowing of explosive gas on the bullet as it exits the muzzle, or both.

Another benefit of suppressor use is that the sound of gunfire is less annoying to surrounding landowners, neighbors, or others in the outdoors. A shooting range or parcel of hunting property where people use suppressed firearms is much less likely to be shut down due to public outcry.

For military and tactical purposes, a good suppressor can reduce the sound and flash signature of a firearm so it’s more difficult for an enemy to determine exactly where gunfire is coming from. Suppressors can help squads maintain communication better when clearing rooms since suppressed gunshots are much less punishing to the ears and nervous system of the user and any squad members than unsuppressed shots.

How are silencers or suppressors made?

Generally speaking, there have historically been two main types of silencer design: baffle stack or monocore. (3D-printed suppressors are also becoming wildly popular, but the designs can generally be termed “monocore” in principle. More on that below.)

In a baffle stack suppressor, several separate sections called baffles, usually generally cylindrical/cone-like in shape, are stacked atop one another to create a series of partitions and passages that helps disperse and redirect the expanding gases of a gunshot. These baffles are either slid inside an outer tube or sleeve, with the end caps threaded or welded on, or in some more advanced designs, the outer skirts of the baffles themselves are welded together precisely to form the “tube” of the suppressor (except in this case there is no separate outer tube). This type of baffled suppressor can be much lighter and theoretically stronger than a traditional design with separate baffles and an outer tube. SIG SAUER popularized this type of suppressor design a few years ago and transformed the industry, but now the 3D-printed approach is likely to become the gold standard (see below).

Are silencers legal in the USA?

Yes, with some caveats and qualifications. At the time of this writing, silencers are legal for ownership by non-prohibited persons under federal law in all 50 states but are only legal under state law in 42 states. Silencers or suppressors are considered “NFA” items, meaning they fall under the purview of the 1934 National Firearms Act and Title II of the Gun Control Act of 1968 which regulate, on a federal level, items such as machine guns, short-barreled rifles, “sawed-off” shotguns, “destructive devices,” suppressors, and certain other firearms called “any other weapons” with certain characteristics deemed to be worthy of additional scrutiny and taxation.

These items can’t be transferred (sold, bought, or given) or manufactured without prior federal approval via a special business/manufacturing license or paperwork filed with the Department of the Treasury’s Bureau of Alcohol, Tobacco, and Firearms and the purchase of a special tax stamp for each item (see below).

Can I legally purchase or make a suppressor?

In the USA, silencers and suppressors are not like typical firearms or firearm accessories that you can (in many states) buy without federal paperwork from private sellers or with a simple background check from your local gun shop. If owning a suppressor is legal in your area, once you fill out the ATF Form 4 (if you’re purchasing an already-made suppressor from an FFL dealer) or ATF Form 1 (if you’re manufacturing your own suppressor), get photographed and fingerprinted, pass an extensive FBI background check, and pay for the special $200 tax stamp for each suppressor, you can get approval to purchase or manufacture a suppressor. Typically the approval process takes between 60 days and a year, depending on how overloaded the system is. Companies like Silencer Shop work to make the process easier and help you with all the forms and paperwork, but you can also just print out the forms yourself and follow the directions on the ATF’s website.

Note: simply threading or taping a hollow container such as a plastic soda bottle to the muzzle of a firearm may have limited effectiveness in lowering the sound signature, depending on the gun and the cartridge being fired. However, in the USA, this is a felony, since you are (according to the law) manufacturing a homemade silencer without a license. Don’t do it. The penalty for manufacturing a suppressor without a license is $10,000 for each offense, plus a minimum of 27 months up to 10 years in federal prison… and the ATF has no sense of humor.

Besides, a well-made suppressor is orders of magnitude more effective and durable than improvised “silencers.”

Best suppressor manufacturers

There are hundreds of reputable suppressor manufacturers in the US, and as noted earlier, with the right paperwork and approval, you can make your own silencers using templates, CAD programs, or your own designs. However, there are a few silencer manufacturers that often rise to the top when discussing the best and most innovative products. This is not an exhaustive list, but here are some silencer makers to check out:

• SilencerCo
• AAC
• Gemtech
• YHM
• Bowers Group
• SIG SAUER
• Dead Air
• Thunder Beast
• Silencer Central “Banish”
• Elite Iron
• SureFire
• Griffin Armament
• HuxWrx