wheelgunner

I didn't see this listed and thought somebody might like to peruse the info. Note, this is simply information I've collected and can't attest to its accuracy.

Facts on noise levels:
1. Decibels measure sound pressure and are logarithmic. That means that only a 3db increase almost doubles sound pressure, a 6db increase quadruples sound pressure, etc.
2. Gradual hearing loss may occur after prolonged exposure to 90 decibels or above.
3. Exposure to 100 decibels for more than 15 minutes can cause hearing loss.
4. Exposure to 110 decibels for more than a minute can cause permanent hearing loss.
5. At 140 dBA noise causes immediate injury to almost any unprotected ear.
6. There is also the more extreme ‘acoustic trauma’, which is an immediate loss of hearing after a sudden, exceptionally loud noise such as an explosion.

Comparative noise levels and length of time for damage to occur
Jet engine taking off 140 dB Instant damage
Thunder/Ambulance siren 119 dB 3 minutes
Hammer drill 113 dB 15 minutes
Chain saw/Earphones/Concert 110 dB 30 minutes
Bull Dozer 105 dB 1 hour
Tractor/Power tools 96 dB 4 hour
Hairdryer/lawnmower 90 dB 8 hours

Noise levels of firearms:
.22 caliber rifle 130dB
.223, 55GR. Commercial load 18" barrel 155.5dB
.243 in 22" barrel 155.9dB
.30-30 in 20" barrel 156.0dB.
7mm Magnum in 20" barrel 157.5dB.
.308 in 24" barrel 156.2dB.
.30-06 in 24" barrel 158.5dB. In 18" barrel 163.2dB.
.375 18" barrel with muzzle brake 170 dB.
.410 Bore 28" barrel 150dB. 26" barrel 150.25dB. 18" barrel 156.30dB.
20 Gauge 28" barrel 152.50dB. 22" barrel 154.75dB.
12 Gauge 28" barrel 151.50dB. 26" barrel 156.10dB. 18" barrel 161.50dB.
.25 ACP 155.0 dB.
.32 LONG 152.4 dB.
.32 ACP 153.5 dB.
.380 157.7 dB.
9mm 159.8 dB.
.38 S&W 153.5 dB.
.38 Spl 156.3 dB.
.357 Magnum 164.3 dB.
.41 Magnum 163.2 dB.
.44 Spl 155.9 dB.
.45 ACP 157.0 dB.
.45 COLT 154.7 dB.

Properly fitted earplugs or muffs reduce noise 15 to 30 dB. The better earplugs and muffs are approximately equal in sound reductions, although earplugs are better for low frequency noise and earmuffs for high frequency noise.

Using muffs and plugs together: Take the higher of the two and add 5 dB. 30 plug with 20 muff gives an effective NRR of 35.

If you are shooting by yourself, with plugs and muffs on, you get to shoot up to a thousand rounds without damage (louder ammo/gun and the allowable drops by a factor of 5). Shoot with other people and you have to add all the rounds shot cumulatively (10 people shoot 100 rounds and everybody's done for the day; toss a handcannon or 30 cal rifle in and you're back down to 200 rounds cumulative). If you shoot on an indoor range then all the rounds fired while you are on the range go into your total. So you can see that it doesn't take very long on a range to have a thousand rounds popped off around you.

Don't forget about bone conduction of concusive sound waves. The mastoid bone will transmit the sound vibrations directly to you inner ear where the cochela and the hearing nerves resides. Constant exposure to this kind of concusive sound waves, ie: 50 BMG, industrial heavey machinery, will result in the degradation of your hearing quality. Even with ear muffs, bone conduction is a big factor in hearing.

bad-andy

Just wondering if :
air density
temperature
humidity
have an affect on the decibel levels?

spanky

great post! very accurate info -- thanks for contributing!

ripsaw

Yes, excellent post. Now i know why noone that has seen combat can hear a dern thing, probably don't care what anyone says anyway.

Kimura1

Thanks for all the info but I would like to know the recovery.. Say I shoot 50 rounds without hearing protection or 1000 rounds with hearing protection, how long will it take my ears to be how they should? I have gone a few months without shooting and I never notice any difference. Only the nights after range trips do I notice it, though I do always have to have some background noise or the ringing will take over.

Michael

Most damage is cumulative over time.
Only actual testing can quantify it.
A single serious event can up the effects.
There are a lot of noises in our daily environment that can effect hearing.

Tinitis is undetectable and untreatable.

sinead

Found these sources on decibel levels on various length barrels, various calibers, suppressed and unsuppressed, with and without muzzle brakes:

http://www.silencertests.com/results.htm

http://www.elcaudio.com/decibel.htm

www.elcaudio.com/tablesforweb.pdf

bcollida

I'd really like to buy a M1a and love the scout squad in walnut AA9122.

The retailer located by me as a National Match in Walnut NA9102.( 22 inch barrel) which is also pretty cool.

My biggest concern with either of these guns is the sound level of the 308.

I currently shoot 223 ammo out of AR 15 type carbines

My questions are:

1) is there any difference is the decible level between the 18 inch and 22 inch barrel.

2)is there readily available 308 ammunition that might be "less loud" than standard.

I don't know anyone that has a 308. I mostly concerned that these guns are going to sound like a cannon compared to the 223. I live on a farm and my neighbors tolerate my AR 15s. I dont want to send them over a cliff

This is a for fun gun with no real purpose other than to shoot at steel plates

can anyone comment on the sound level between the 18 and 22 inch barrels
can anyone comment on how sound level between the 308 and the 223 with an 18 inch barrel.

your thoughts are greatly appreciated