a supercavitating water - entry projectile having empennage on the aft end which provides both aerodynamic and hydrodynamic stability and a supercavitating nose section is provided . a representative projectile is a subcaliber munition adapted for use in a 25 mm weapon using a sabot currently in use with the m919 round . the projectile has circumferential grooves around its center section to match these sabots . a key feature in the invention is the size and shape of the nose section . the projectile has a novel high strength extended blunt nose section followed by a truncated conical section which angles towards the body of the projectile in the range of five degrees . during underwater trajectory , the entire projectile is contained within the cavitation bubble formed by the blunt nose tip . the projectile &# 39 ; s aft empennage , which provides both aerodynamic and hydrodynamic stability , fits within the bore of the weapon .