re: SHARE Act / Hearing Protection Act shelved indefinitely

My post on the OT lounge about rifle acoustics copy and pasted here except for a spelling error correction.

I do [some] acoustic engineering so I'm familiar with the math. Lets do some math.

Google says an AR15 shooting standard ball ammo will measure around 158dBL at 1m. Your hearing is instantly damaged at 140dBL without hearing protection. At 200m away the sound would be 108dBL

A suppressed AR15 is measured around 136dBL for a good quality can. At 200 meters the sound level would be measured at 88dBL. That's a little louder than standing beside a running lawnmower. Can you hear a lawnmower when you are standing beside it? That's how loud an AR15 shot suppressed from 200m away is. But... that is just the measurement of the muzzle blast. Any high powered rifle the bullet is supersonic and is propagating a supersonic shock wave (sonic boom) as is moves down range. That is the "crackling" sound you will hear down range. Again google search finds some testing that shows a bullet's supersonic shock wave will be in the range of 135+ dBA and there is nothing a suppressor will ever do to mask that sound signature. That is a 135dBA noise propagating down the lane of fire you that you should easily be able to hear unless you are deaf. -6dB per doubling of the distance away from the shock wave you are still over 100dBL when you are over 56M away from where the bullet passes by. That shock wave noise level is constant until you hit about 1300fps then it starts dropping off quickly. Plugging numbers into my ballistics calculator, standard XM193 556 ball ammo will not drop down to that velocity level until you hit the 600 yard range.