Deciphering Gunshot Recordings

Audio gunshot recordings can be helpful for crime scene reconstruction, estimation of the shooter's location and orientation, and verification of eyewitness accounts. The audio evidence can include the muzzle blast, the shock wave signature if the projectile is traveling at supersonic speed, and possibly even the characteristic sound of the firearm's mechanical action if the recording is obtained close to the shooting position. To investigate the acoustical phenomena associated with gunshot evidence, a systematic set of rifle shots were made from distances ranging from 10 meters to nearly 800 meters away from the recording microphone. This paper summarizes the primary acoustical evidence derived from these recorded gunshots, and suggests several strengths and weaknesses of gunshot analysis for forensic purposes.