Experimental Determination of the Effect of Rifling Grooves on the Aerodynamics of Small Caliber Projectiles

*† Simplifying assumptions about projectiles are often made in order to complete wind tunnel tests, range experiments and numerical calculations to determine their aerodynamics without fully understanding the ramifications of these assumptions. This study was undertaken to determine the effect of the rifling grooves and non-dimensional spin rate on the aerodynamics of a small-caliber projectile at multiple downrange locations (Mach numbers). The experimental range tests showed the rifling grooves only had an effect on the roll damping at the muzzle velocity and that the groove effects appeared to be mitigated by the increasingly over-spun projectile. The spin rate was found to have a possible effect on the roll damping, the pitch damping and the Magnus moment, but experimental error makes it difficult to quantify.