Simulation of Asymmetric Shot Start in Small Caliber Ammunition

Abstract

Recent short-barrel experiments have indicated that primer ignition of small caliber ammunition is sufficient to begin projectile motion and engraving. High-speed video of these experiments also reveal that the early projectile motion is not symmetric with the nominal gun bore centerline. This early motion can lead to asymmetric engraving and has the potential to produce a mass asymmetry in the projectile leading to decreased accuracy due to increased dispersion. In this work the early motion of the projectile is simulated in order to determine the magnitude of any mass asymmetry resulting from the asymmetric shot start. The simulations indicate that the asymmetric shot start results in a modest engraving asymmetry and therefore a small mass asymmetry.