Gunfire Sound Levels
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Gunfire Noise Level Reference Chart [/align]Below we have listed critical data describing peak sound pressure levels produced by firearms used in shooting and hunting sports. A serious byproduct of this exposure is sensory-neural hearing loss, which cannot be restored to normal. With the introduction of MUZZLE BRAKES and PORTING, the risks of hearing loss dramatically increase. Use this chart as a reference guide for promoting the need of using adequate hearing protection.
Notations
Keep in mind that conversational speech is approximately 60-65 dB, and the threshold of pain is considered to be 140 dB. According to Dr. William Clark, Ph.D. senior research scientist in charge of the NOISE LABORATORY at the Central Institute for the Deaf in St. Louis,
the damage caused by one shot from a .357 magnum pistol, which can expose a shooter to 165 dB for 2msec, is equivalent to over 40 hours in a noisy workplace.Dr. Krammer, Ph.D., Ball State University, Muncie, Indiana has documented the following pressure levels.
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
The above averages are for all types of ammunition used in these firearms, and should be considered fairly representative. No wonder we hear numerous reports about hearing loss as a result of firearms including acoustic traumas that take hearing completely as a result of one shot. Imagine what the noise levels must be when we incorporate muzzle brakes or porting into firearms, or have a gun explode near the ear due to malfunction.
http://www.freehearingtest.com/hia_gunfirenoise.shtml
decible levels
