Experimental Investigation of the Projectile type on Sound Pressure Levels Fired with 9 mm Gun

Abstract

Throughout of the firing process, too much noise is occurred in the form of an blast wave caused by the discharged gas. An instantaneous and high amplitude sound pressure is created by the explosion and this pressure causes a harmful noise to the human ear. The main sources of the generated sound can be categorized as the explosion at the barrel exit, projectile velocity and the sound produced when the projectile hits the target. Subjects such as subsonic and supersonic projectiles, projectiles with different geometries, silencer systems are very important to reduce this explosion noise created by gun systems. Within the scope of this study, the peak sound pressure levels after firing the subsonic and supersonic projectiles from a 9 mm gun were experimentally measured at different positions. The measurements were realized at 23 different positions. The results of this study showed that in all measurement positions, supersonic projectiles have higher peak sound pressure levels (db) than subsonic projectiles. The peak sound pressure levels decreased with increasing distance from the gun barrel exit a as expected. Also, it has been determined that subsonic and supersonic projectiles give close results to each other in the measurements made at the same level with the barrel at y-axis direction.