Impulse noise measurements of M16 rifles at Marine Base Quantico

This paper describes a study conducted at U.S. Marine Corps Base Quantico to determine firing range impulse noise levels and assess noise exposures. Measurements were performed with M16A4 rifles at an outdoor firing range, using a 113-channel array of 6.35 and 3.18 mm microphones that spanned potential locations for both shooters and instructors. Data were acquired using 24-bit cards at a sampling rate of 204.8 kHz. Single weapon measurements were made with and without an occupied range, with a shooter and with a remotely triggered gun stand. In addition, measurements were made with multiple shooters to simulate exposures for a realistic range environment. Results are shown for the various range configurations as a function of angle and distance. Analyses include waveforms, spectra, and peak levels, as well as the 10 ms equivalent level. All measurements met guidelines of the applicable military standard MIL-STD-1474E and the data are shown to be of high fidelity and useful for future in-depth analyses and noise dosage model development.