Suppressor Map

The Legality and Function of Suppressors

Banner_250x300The misinformation concerning the ownership and function of firearm sound suppressors (also known as “silencers”) is virtually peerless in the firearms community. Those not well-informed will say a myriad of things ranging from “you need a permit to own a silencer,” to “those are illegal, and only assassins use them.” Neither of these is true. Then, of course, there is the confusion about how effective they are – most who do not know better will again claim that they reduce the report of a firearm down to the “puff” that we hear in Hollywood movies. False, yet again.

First, let us look at the legality of sound suppressors. These are NFA items just like any other – short barreled rifles, short barreled shotguns, machine guns, etc. – which are all legal to own and use in general, with some regulation by the federal government and some states unfortunately banning them.

At this time, there are 39 states in which suppressor ownership is legal, as shown in the image compiled by Advanced Armament Corporation.(1)

I will not go into the specifics of how to acquire suppressors or other NFA items, but will address a core misconception – you do not need a “permit” for any NFA item. You pay a $200 tax stamp for each NFA item (each SBR, each suppressor, etc.), and wait the requisite time it takes for the BATFE to process your application. You have to meet a few requirements legally, but if you qualify for a concealed carry permit then you will likely qualify for an NFA item as well.

Second, the function of suppressors. I’m not a physicist or an engineer, but the science of how suppressors work makes it fairly obvious that they cannot completely silence the firearm. Suppressors have conical (or other shapes) baffles inside of a tube – these baffles effectively slow the extremely rapid expansion of gasses that creates the “boom” we are accustomed to hearing from the loud end of a firearm. This entails that they cannot reduce the noise of the action (such as the bolt carrier moving, the trigger resetting, etc.) nor the “sonic crack” generated by the projectile breaking the sound barrier (if the rounds are supersonic, which most rifle rounds are). Thus, the suppressor can only reduce the noise from one aspect of the firearm’s overall sound – expanding gasses. If you look at the sound reduction data on most suppressors, they reduce the decibel (dB) rating only a small amount from a centerfire rifle cartridge. For instance, an unsuppressed AR15 will generally rate about 170 dB, with minor variance depending on a wide variety of variables (ammo type, barrel length, muzzle device, etc.), and adding a Silencerco Saker 556 (of which I am a proud owner) reduces the report to about 134 dB, under the OSHA limit on “impulse” (momentary) sounds of 140 dB (2). Note that these numbers are in a logarithmic scale – in other words, 140 vs 134 is not a difference of approximately 4%, but of 6 times; 140 dB is six times louder than 134 dB. Look at this chart to get an idea of some other values of sound levels.

(3)

I hope this (very) cursory look at the legality and technology behind suppressors will help enlighten you and others regarding this highly misunderstood part of the firearms industry. In closing, I would like to note that suppressors, in all reality, simply take some of the “edge” off of the noise and concussion of a firearm. They are great tools for getting inexperienced shooters into firearms – the blast is reduced, and the need for hearing protection is often times eliminated, making for better communication at the range and – when you may need it most – at home.

1. http://www.advanced-armament.com/Ownership-Information_ep_42-1.html

2. http://silencerco.com/products/saker/

3. http://precisionrifleblog.com/2015/02/20/better-smaller-lighter-the-new-thunderbeast-suppressors/rifle-silencer-noise-examples/