Duplex combustible cartridge case

Claim 1

A duplex combustible cartridge case for a fully telescoped round of ammunition comprising, a laminated propellant charge of substantially cylindrical configuration composed of dissimilar materials and having an axial bore therethrough, the laminations in said propellant charge being comprised of a conventional propellant sandwiched between layers of felted nitrocellulose, a projectile positioned in the forward portion of the bore of said propellant charge, a tubular igniter positioned in the rearward portion of said propellant charge immediately aft of said projectile, a molded propellant supplementary charge positioned around the igniter tube, the inner surface of the inner layer of felted nitrocellulose being in contact with the outer surface of said supplementary charge, means for threadably connecting said tubular igniter to the base of said projectile, and a primer disposed within the rearwardmost portion of said igniter, the peak pressure of said propellant charges remaining substantially constant while the muzzle velocity of the ammunition is increased by varying the ratio by weight of propellant to nitrocellulose.