Abstract:
1. For use with a gun having a firing pin, a cartridge having a hollow casing adapted to contain a powder charge and having a base at the rear end, said base having an axially extending aperture, a primer mounted in the forward portion of said aperture, retaining means for limiting movement of said primer in a forward direction, a piston slideably mounted in the rearward portion of said aperture behind said primer, said piston having a surface facing said primer, a forwardly extending projection on said surface, said piston adapted to be driven forward by said firing pin causing said projection to strike said primer and deform the same against the resistance of said retaining means, the impact of said projection upon said primer causing initiation of the latter and ignition of the charge whereby propellent gases are produced which act upon said primer and said surface, said piston being rearwardly accelerated independently of said primer by the action of the propellent gases upon said surface to thereby impart a rearward acceleration to said firing pin.