January 26th, 2019

Suppressors — Why You Still Need Hearing Protection

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Silencer-equipped AR photo courtesy The Silencer Shop.

OK, you’ve paid the tax stamp and acquired your new suppressor (aka “silencer” or “moderator”). Do you still need to wear earplugs or muffs? Absolutely. Even with that expensive new “can”, your rifle could be generating over 140 decibels (dB) of noise — about the same as as an unmuffled 9mm pistol shot. That’s loud enough to create permanent hearing loss with repeated exposure.

Firearms Are Loud: 140 dB to 175 dB

Audiology group ASHA explains: “Exposure to noise greater than 140 dB can permanently damage hearing. Almost all firearms create noise that is over the 140-dB level. A small .22-caliber rifle can produce noise around 140 dB, while big-bore rifles and pistols can produce sound over 175 dB. Firing guns in a place where sounds can reverberate, or bounce off walls and other structures, can make noises louder and increase the risk of hearing loss. Also, adding muzzle brakes or other modifications can make the firearm louder. People who do not wear hearing protection while shooting can suffer a severe hearing loss with as little as one shot[.] Audiologists see this often, especially during hunting season when hunters and bystanders may be exposed to rapid fire from big-bore rifles, shotguns, or pistols.” Source: ASHA, Recreational Firearm Noise Exposure.

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Suppressors, On Average, Reduce Noise Levels about 30 Decibels
In an article for Ammoland, gunwriter Sam Hoober says that you can expect about 30 decibels (dB) of noise reduction from the average suppressor: “Looking at a few different products, SilencerCo attests 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, attests a 23 dB to 33 dB reduction or down to 127 dB. Liberty Suppressors, another manufacturer, attests a reduction of 24 dB to 38 dB, depending on model and other factors. In short, we can presume something on the order of 30 dB of attenuation as an average.”

Using that 30 dB number you can quickly discern that you’ll still need hearing protection — good hearing protection — when shooting any suppressed firearm (even a .22 LR). “Spikes of 130 dB and more can result in permanent hearing damage instantly”. Source: NRA Blog.

The Myth of the “Quiet” .22 LR
The NRA Blog notes that “many rimfire shooters, particularly those using the beloved .22 Long Rifle cartridge, argue that the small .22 LR caliber doesn’t produce enough sound to damage your hearing”. So, is that really true. or is it a myth?

In fact, a .22 LR can be much louder than you think — a .22 LR pistol can produce sound levels of 134 dB. That’s well above the normal human pain threshhold.

Sound Levels for Common Noises:

9mm Luger pistol: 160 dB

Jet aircraft engine (near): 140 dB

.22 LR pistol: 134 dB

Normal human pain threshold: 120 dB

Noisy Nightclub: 110 db

Riding Motorcycle at 65 mph: 103 db

Power Lawnmower: 95 dB

Hearing damage possible: 85 dB (sustained for 8+ hours)

Ringing Telephone: 80 dB

Normal conversation: 60 dB


The Risk of Hearing Loss
Hearing loss can be progressive and irreversible. If you are a shooter, this is serious business. As the NRA Blog cautions: “You may not even realize you’re harming your hearing. Hearing loss occurs gradually, and can go effectively unnoticed until symptoms become severe. By then, the damage is done.”

Nobody wants to go deaf. But we often see shooters without effective hearing protection when they are walking around a few yards behind the firing line. That’s bad — even if you are away from the firing line, gunshot noises can damage your hearing. You MUST use effective hearing protection every time you go to the range. Good foam earplugs costs mere pennies but they can prevent deafness in your later years. Many folks also wear muffs over plugs.

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April 27th, 2018

Suppressors for Hunters — What You Need to Know

There is an informative article on the NRA’s American Hunter website regarding suppressor use for hunting. The article, What Hunters Need to Know About Suppressors, answers common questions about licensing, tax stamps, and suppressor types. The article explains the history of the $200 tax stamp which must be paid when acquiring a suppressor:

“Why the Tax? In 1934 … the federal government, while battling gangsters such as Al Capone, heavily restricted silencers with passage of the first National Firearms Act. Hoping to gain an advantage on criminals that often had better weapons than cops, the Feds placed a mandatory ‘sin’ tax on silencers that was so high it would effectively ban their purchase by all but the wealthiest individuals. In 1934, $200 was the equivalent of $3,500 today. The $200 tax still stands despite no evidence that a simple metal tube is capable of causing crime.” — American Hunter

The American Hunter article also discusses how well suppressors actually reduce noise. User should be aware that the sound level of a large, centerfire hunting cartridge will still exceed 130 decibels (dB) on average, even with a typical suppressor (silencer) in place. For that reason, we recommend that hunters continue to wear ear protection even when they shoot suppressed.

For example, Thunder Beast Arms says its latest Ultra 9 Suppressor will reduce the report of a .308 Win to 132-134 dB: “The ULTRA 9 will suppress a typical .308 bolt-action rifle down to approx. 132-134 dB. It also has very little or no ‘first round pop’ (FRP) in most applications.” NOTE: These dB levels are measured in accordance with MIL-STD-1474D using BK 2209 SLM offset one meter from muzzle.

How Loud Are Unsuppressed Rifles?
Firearms Are Loud — 140 dB to 175 dB. Audiology group ASHA explains: “Almost all firearms create noise that is over the 140-dB level. Exposure to noise greater than 140 dB can permanently damage hearing. A small .22-caliber rifle can produce noise around 140 dB, while big-bore rifles and pistols can produce sound over 175 dB. Firing guns in a place where sounds can reverberate, or bounce off walls and other structures, can make noises louder and increase the risk of hearing loss. Also, adding muzzle brakes or other modifications can make the firearm louder. People who do not wear hearing protection while shooting can suffer a severe hearing loss with as little as one shot[.] Audiologists see this often, especially during hunting season when hunters and bystanders may be exposed to rapid fire from big-bore rifles, shotguns, or pistols.” Source: ASHA, Recreational Firearm Noise Exposure.

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How Much Does a Good Suppressor Really Reduce Firearm Sound Levels?
That depends on the rifle, the cartridge, and the effectiveness of the suppressor. The American Hunter article explains: “Suppressors retard the speed of propellant gases from the cartridge that rapidly expand and rush out of the barrel. It’s these gases that produce the loud boom that’s heard for miles. A suppressor’s series of internal baffles slows these gases so they are not all released at once, thereby muffling the sound.” Many good commercial suppressors can achieve 30-35 dB sound suppression. However, Zak Smith of Thunder Beast Arms says: “There are a bunch of manufacturers who publish values that are not reproducible, or use an ad-hoc test instead of a mil-spec test. In many cases we’ve tested the exact same suppressors they’ve advertised with 30-40 dB reductions and found they are actually in the high 20s instead.”

Again, for this reason, we recommend that hunters use ear protection, such as electronic muffs, even when shooting suppressed.

Choosing a Suppressor for Hunting Use
The American Hunter article explains that there are many types of suppressors on the market. Bigger suppressors are heavier, but they normally are more effective. You also have a choice in muzzle attachments:

“For most hunting applications, direct thread is the best choice. If you intend to buy only one suppressor yet you have multiple guns, it’s advantageous to buy a model sized and rated for the largest caliber you intend to use. While a suppressor made specifically for a .223 Rem. will reduce the sound of that round slightly better than a model made for .30 caliber, for example, you can use a .30-caliber can for smaller calibers — but not vice-versa. In general, the bigger the can, the more it reduces sound. Smaller suppressors, however, are easier to carry in the woods.” — American Hunter

How to Apply for a Suppressor
To acquire a quality suppressor, you’ll first need to shop around, comparing verified performance. Unfortunately some manufacturer’s dB claims are exaggerated. Give due consideration to size, weight, and durability. When you’ve selected a brand and model, find a Class 3 dealer authorized by the ATF to sell suppressors. You must fill out ATF Form 4, get fingerprinted, and pass a background check. Along with two completed copies of Form 4, submit your fingerprint card, passport photo and a check for $200 to the ATF. Then you wait for the ATF to process your application. American Hunter says the average ATF suppressor processing wait time is now nine months.

BENEFITS OF SILENCERS

NOISE REDUCTION
According to OSHA, the threshold for a hearing safe impulse noise is 140 dB. Without hearing protection, exposure to any impulse noise over 140dB causes varying degrees of permanent noise-induced hearing loss, which can also lead to tinnitus. Most well-engineered silencers take the dB level of their host firearm well below 140 dB, making those silencers effective primary hearing safety devices. You should always still wear hearing protection (muffs or plugs) when using suppressors.

RECOIL REDUCTION
By containing the explosion at the muzzle, suppressors significantly reduce perceived recoil energy, reduce the rifle’s rearward movement on recoil, and reduce rifle torquing and muzzle flip. The reduction of recoil (and rifle torquing/hopping) lessens shooter fatigue and helps the shooter get his sight picture back on target rapidly after firing. With smaller calibers, a suppressor may enable the shooter to maintain a nearly-continuous sight picture, following the shot into the target. In addition, by reducing felt recoil (and muzzle blast), a suppressor can help inexperienced shooters avoid flinching.

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