Noise exposure profiles for small-caliber firearms from 1.5 to 6 meters

Abstract

Small caliber firearms (rifles, pistols and shotguns) are commonly used at outdoor firing ranges for training in shooting skills, job qualification and for recreation. Firearm noise from fifty-four weapons was measured at an outdoor range in the near field (6 meters and closer) of the weapons using a radial array of 18 microphones centered on the shooter’s head. Each weapon was fired five times and the microphone array was sampled at 200 kHz with at least 16-bit resolution. Peak sound pressure levels and damage risk criteria (e.g. MIL-STD 1474D, 8-hour Equivalent A-weighted Level (LAeq8), and Auditory Hazard Assessment Algorithm for Humans (AHAAH)) were computed for each microphone and compared across weapon type, caliber and load. The acoustic propagation from the muzzle to the microphone was modeled using a simple image source over a reflecting plane. The impedance of the ground was estimated from the observed data and was used to compare the measured waveforms with the estimated waveforms. These data will be used to model the exposures for multiple shooters and observers standing at or behind the firing line.

Prevention of Noise-Induced Hearing Loss from Recreational Firearms

“…The maximum peak sound pressure levels (SPLs) from firearms range from $140 to 175 dB. [7][8][9][10][11][12][13] The majority of recreational firearms (excluding small-caliber 0.17 and 0.22 rifles and air rifles) generate between 150 and 165 dB peak SPL. The general range of peak SPLs measured at the left ear of a right-handed shooter for various categories of recreational firearms are summarized in Table 1.…”

“…The general range of peak SPLs measured at the left ear of a right-handed shooter for various categories of recreational firearms are summarized in Table 1. [7][8][9][10][11][12] Pistols have shorter barrel lengths than rifles and shotguns and rank high in peak SPL due in part to the closer proximity of the muzzle to the ears. Shorter barrel lengths found in both youth firearms and assault rifles also increase the SPL measured at the shooter's left ear.…”

“…Shooting in groups increases the auditory hazard to the ears of the shooter, because the exposures come from both their own firearm and from other, nearby shooters. 9 Increasing the distance between shooters and minimizing the number of shots fired reduces the risk of NIHL. Shooting at Figure 4 Strategies for protecting hearing.…”