Damage of Auditory Perception Following Firearm Use: An Experimental Study Conducted on 80 Patients
Noises related to the firing of a weapon derive from three sources: 1. noises produced by the firing and ejection mechanism of the weapon; 2. noises produced by the firing gas expansion of the weapon; 3. noises produced by the projectile in the air and at the moment of impact. With regard to the first point, in ordinary repeating weapons there is only the noise of the trigger pull and the firing pin striking the primer; in automatic weapons there may be the noise of the beating mass striking, retroceding and recambering a cartridge [1]. Such noises are almost always masked by the sounds of the actual firing and assume some prominence only in weapons equipped with silencers [2]. The actual firing, on the other hand, is produced by the rapid expansion of gases that exit the muzzle of the weapon with a velocity that can be twice that of the projectile and with a pressure of several hundred atmospheres [3, 4]. Three basic components can be distinguished in shot noise.