DIN EN ISO 17201-2:2004-10

This part of the standard series provides a calculation procedure for the acoustical source energy of the muzzle blast and the projectile sound on the basis of propellant, launch speed and bullet weight. There are two basic sources that dominate the shooting sound from a rifle or pistol shot, the muzzle blast and the projectile sound. Both sources are basically different. The muzzle blast is caused by the expanding gases of the propellant at the muzzle. The muzzle blast stems from a more or less spherical volume of these gases at that moment when the expansion speed becomes subsonic. The projectile sound is caused by the supersonic flight of the projectile along the trajectory from the muzzle to the target or to a point on the trajectory where the projectile speed becomes subsonic. The projectile sound stems from a section of the trajectory that coherently radiates a shock wave into a certain direction. In general, the procedures to estimate the source energy of these sources rely on the estimation of energies that are involved in the related processes. The procedures give estimates for the fraction of these energies that transforms into acoustic energy. The result of the estimation are acoustical source data with respect to energy, direction and frequency content.