Patent ID: 7222573
Filing Date: 2007-05-29
Classification: F42B

Abstract:
1. In a projectile for an air arm molded as a body of revolution about a longitudinal axis comprising a head portion dimensioned for free sliding in the bore of an air arm and a skirt portion of frusto-conical form of which the rearward end is dimensioned to be in interference fit with said bore and the forward end is joined with the head portion in a reduced diameter waist, the frustum being shell-walled and having a central recess opening to the rear and extending forwardly into the head portion, an improvement wherein said projectile has an external surface form characterized by a parabolic head which smoothly transitions axially into a hyperbolic skirt, said projectile further comprising one or more vanes formed substantially symmetrically on the outer surface of said head portion, each vane extending axially in a helix configuration with a characteristic pitch which varies along the axial extent thereof.