Why hearing protection when shooting is important...

[benEzra]

http://www.freehearingtest.com/hia_gunfirenoise.shtml

Not sure if these figures are straight dB or dBA.

Table 1. SHOTGUN NOISE DATA (DECIBEL AVERAGES)

.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

Dr. Krammer continues to say that shotgun noise averaged slightly more that 150dB. This is approximately 14dB beyond the threshold of pain, and more than sufficient to cause sudden hearing loss with complications.


Table 2. CENTERFIRE RIFLE DATA
.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
.30-06 in 18 _" barrel.......................163.2dB
.375 — 18" barrel with muzzle brake...........170 dB

Krammer adds that sound pressure levels for the various pistols and ammunition tested yielded an average mean of 157.5 dB, which is greater than those previously shown for shotgun and rifle noise levels. There was also a greater range, from 152.4dB to 164.5dB, representing 12 dB difference, or more than 10 time as much acoustic energy for the top end of the pistol spectrum. It should be noticed that this figure of 164.5 dB approaches the practical limit of impulse noise measurement capability inherent in most modern sound level meters.


Table 3. CENTERFIRE PISTOL DATA
.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

For those who don't grok decibels, it's a logarithmic scale (usually log10); a 3dB difference equals twice the radiated acoustic energy, and a 10dB difference is ten times the radiated acoustic energy. The ear perceives a 10dB difference as a doubling in volume, and IIRC the average person can just barely distinguish a 1dB difference. A car interior at highway speeds is 60-70 dB, a vacuum cleaner in the 80's to 90dB, I think.

Contrary to popular belief, there doesn't seem to be a huge difference between shotgun, pistol, and rifle noise levels, although the sound spectrum is undoubtedly different. There is a correlation with caliber (e.g., .30-06 is louder than .223 and .357 is considerably louder than 9mm or .45), but the most striking difference to me is how much louder a muzzle brake makes a hunting-caliber rifle (nearly 6 dB louder than an unbraked rifle, using an 18" .30-06 as a comparison, or translates to approximately 4 times the radiated acoustic energy). There's a tight correlation with barrel length (shorter is louder for any given caliber), but also less correlation with velocity than I expected (i.e., a slowpoke .30-30 round out of a 20" barrel is a smidgen louder than a faster but much smaller .223 round out of an 18" barrel). For all the 7.62x39mm shooters out there, I'd assume the sound levels would be about the same as .30-30, which it resembles.

Personally, I always double up when shooting (foam earplugs AND slimline earmuffs, I like Silencio plugs and Peltor Shotgunner muffs), but these figures are a good argument for doing that. Consider that typical hearing protection reduces the noise by ~30 dBA, and you're still looking at >130dB for some guns, and >=140dB when shooting a heavy hunting-caliber rifle with a muzzle brake, so with either plugs alone or muffs alone, you could still have sound levels higher than you'd like. Wear both, if you comfortably can.

The moral of this story is, protect your ears! If you are a hunter and need to hear your surroundings, you may want to look into electronic muffs that amplify faint sounds and block loud sounds (I've tried some, they're awesome). But don't go to the range or afield to do any shooting without packing plugs or muffs; your ears will thank you.

If you are new to the shooting sports, don't scrimp on your ear protection. Get some comfortable plugs and muffs and wear them religiously. Going without hearing protection isn't "tough," it's stupid.

</public service announcement> :)

[Redneck Socialist]

1. Great advice

a combination of shooting without ear protection when I was younger and too many rock concerts pooched the hearing in my right ear. I have significant hearing loss in that ear and constant ringing in both.

Don't be like RS kids, wear that hearing protection.

Like you bE I now double up on hearing protection when at the range. Better late than never I guess.

[Deep13]

2. WHA-A-AT???

:evilgrin:

[JustABozoOnThisBus]

3. Good advice, but there's got to be more to the story

I wear ear protection now, but there must be more factors than just "decibels".

A long-barreled "goose" 12-ga aimed at the sky just doesn't seem very loud. A little 9mm handgun shot in an indoor range is painfully loud (if you forgot to put on the ear muffs). A magnum rifle at the next bench at the outdoor range is loud. If the same round is shot from a rifle with a "mussle brake", the noise seems highly amplified.

It's good to see that the military is using ear protection during basic training. They didn't use it when I was in basic, and those M14's were loud. Louder than the M16.

[benEzra]

4. Proximity, reflection, and frequency, IMHO...

a long-barreled shotgun puts the source of the sound probably twice as far from your ears as a pistol. Since sound intensity decreases by the square of the distance, the sound intensity at your ear from the shotgun would be 1/4 that of the pistol, i.e. 1/(2^2). The shotgun also puts out a much larger volume of gas (.729 caliber for a 12-gauge vs. .355 caliber for a 9mm), and the sound may have a somewhat longer duration for the shotgun.

When comparing shooting indoors vs. outdoors, walls do make a big difference. Outdoors, you hear mostly sound waves that come directly at you from the firearm, which is only a small percentage of the total acoustic energy. Indoors, a lot of the sound that would ordinarily be dissipated elsewhere gets reflected back at you by the walls, hard floor, and ceiling.

There may also be differences in frequency between different calibers, causing them to be perceived differently. I know that to me, pistol shots sound somehow sharper than rifle shots, with revolvers being worse than semiautos (perhaps because of the gas escape at the cylinder gap). I know that under the roof of my local outdoor range, rifles sound "boomier" and pistols sound more like a "crack" than a "boom."

FWIW, I had a friend with a .22 magnum revolver, and it made you wince even through earmuffs; the sound seemed much higher pitched than the sound of a 9mm.

Regarding rifles with brakes, I agree with you. I suspect that has a lot to do with the direction of the gas stream; I know that with jet aircraft, more sound is radiated to the rear than to the front even when the plane is stationary, because that is the direction of the fast-moving gas, and the sound is generated at the turbulent boundary between the supersonic gases and the stationary air. I suspect that suspect that the sound from a firearm probably has a directional bias, with it being somewhat louder in the downrange direction. A brake takes that supersonic gas and directs it sideways, and the result is definitely increased volume to the sides and rear as compared to a non-braked rifle.