One of the biggest topics in the gun world recently has been suppressors and the prospects for passage of bills that would deregulate them like the Hearing Protection Act and the SHUSH Act. For those who haven’t followed the news, the HPA would remove suppressors – a.k.a. “silencers” – from the list of heavily regulated devices, allowing them to be purchased like a firearm, but without a tax stamp from the ATF. The SHUSH Act would allow them to be sold over the counter like any other firearm accessory.
Suppressors are the reason a number of gun owners have threaded barrels for their pistols, whether the threaded barrel goes in their concealed carry holster or not.
But how well do suppressors really work? It’s worth looking at, as the only experience most people have with a suppressor is when they’ve seen one in a movie.
The typical gunshot produces 140 to 160 decibels of noise. Any noise above 140 dB can produce instant hearing damage, so anything that brings a gunshot below that threshold is worth looking into.
It’s a myth that suppressors make any firearm “silent.” A gunshot is still going to sound like a gunshot; it’s just going to be somewhat quieter. That said, how much quieter?
The truth is there’s an economy of scale. Part of the noise attenuation comes down to the suppressor used. Is it designed for the caliber you’re using or is it more of a generic design intended for multiple calibers? How long/short is the suppressor and how is it made? Those factors make an impact on the noise reduction you’ll experience.
So does the ammunition you use. Supersonic ammunition — anything traveling at 1,125 feet per second and faster — makes a sonic “crack” when it breaks the sound barrier that subsonic ammo doesn’t. Ambient temperature, humidity and elevation also make an impact.
Put a bit more simply, how well a suppressor works on paper can and will differ from how well it will work for you depending on a number of factors, so your mileage may vary.
That said, let’s try to come up with an average noise reduction estimate of sorts.
Looking at a few different products, SilencerCo says their suppressors reduce the sound pressure of a 9mm gunshot to anywhere from 125.7 dB to 131.5 dB, depending on the model. Advanced Armament Co, another popular supplier, claims a 23 dB to 33dB reduction or down to about 127 dB. Liberty Suppressors says their cans reduce the sound of a gun shot from 24 dB to 38 dB, depending on model and other factors as above.
In short, we can presume something on the order of 30dB of attenuation as an average. Since the typical 9mm gunshot produces about 160 dB of noise, that means a suppressor will lower the boom to about 130 dB. It could be more or less – even much less, in some cases – but that’s a reasonable average. You can argue amongst yourselves in the comments if you take umbrage.
Assuming an average noise reduction of 30 dB and a sound level of 130 dB with a suppressor, you’ll still want to wear ear protection. Your fellow shooters and neighbors in the area will appreciate the relative quiet, but you’ll still need to protect your ears.
The louder the noise and the more you’re exposed to a noise level, the more likely hearing damage becomes. Hearing loss can be induced by being exposed to a constant 85 dB noise, which is why OSHA mandates 85 dB be as loud as workplaces get – even industrial ones – without mandatory ear protection.
Noises in excess of 120 dB – which is the sound pressure generated by a jumbo jet on tarmac from 100 yards away – can cause permanent hearing loss if exposure lasts just minutes. Fifteen minutes listening to a 115 dB sound system will probably damage your hearing. An afternoon’s shooting, even if attenuated by a suppressor to that lower level, can still damage your hearing permanently.
To sum up, suppressors don’t “silence” a gun shot by any means. Though they can be very effective and definitely reduce overall noise levels, they still generate – in most cases – sufficient noise to damage your hearing. Thus, if you’re one of the growing number of gun owners who are buying suppressors these days, or plan to if they’re de-regulated, make sure you use it with hearing protection.