Polymeric cartridge assembly

A polymeric cartridge subassembly for use in medium caliber weaponry, comprising:

• a metallic base having a rearward surface, an open forward surface, and a coupling element therebetween, the rearward surface including a primer recess for receiving a primer, the primer recess having an opening extending into an interior portion of the base;
• a polymeric casing having a forward end opening, an opposite end, and a middle body portion therebetween, the forward end opening adapted to receive a projectile, the coupling end sized to and being mated with the base coupling element, and wherein the polymeric casing includes a shoulder portion for couplable engagement with the metallic base forward surface such that a ledge member of the metallic base receives the casing opposite end during subassembly;
• and
• a retaining insert received within a combustion chamber of the polymeric casing, the retaining insert ensuring engagement between the polymeric casing and the metallic base, wherein said retaining insert includes a contoured region for mating with said base, and a cylindrical extension member having a first diameter and extending from said contoured region terminating in an undulation and rim end, wherein said rim end having a second diameter greater than said first diameter.

A method of assembling a polymeric cartridge for use in medium caliber weaponry, the method comprising the steps of:

• securing a coupling end of a polymeric casing to a coupling element of a metallic base such that the coupling element encapsulates an interior combustion chamber of the polymeric casing, and the base includes a plurality of apertures disposed around an arch length of the base and in communication with the combustion chamber of the polymeric casing;
• inserting a primer into a primer recess of the base;
• inserting a propellant charge within the combustion chamber;
• and
• seating a projectile onto a forward end opening of the polymeric casing to encapsulate the combustion chamber, wherein the polymeric casing is formed from a graphene-reinforced polymer matrix composite;
• inserting a retaining insert within the combustion chamber.