The present invention provides a polymer nose for a polymeric ammunition cartridge having a generally cylindrical neck having a projectile aperture at a first end, a shoulder comprising a shoulder top connected to the generally cylindrical neck opposite a shoulder bottom, a side wall extending from the shoulder, a groove positioned around the side wall, a skirt connected circumferentially about the groove to extend away from the groove, wherein the groove and the skirt are adapted to mate to a polymer cartridge.

The present invention provides a metal injection molded ammunition cartridge comprising a metal injection molded bottom portion comprising a primer recess in communication with a primer flash hole that extends into a propellant chamber and a metal injection molded body extending form the metal injection molded bottom portion.

The present invention provides a metal injection molded ammunition cartridge comprising a metal injection molded bottom portion comprising a primer recess in communication with a primer flash hole that extends into a propellant chamber and a metal injection molded body extending form the metal injection molded bottom portion.

The present invention provides a polymer nose for a polymeric ammunition cartridge having a generally cylindrical neck having a projectile aperture at a first end, a shoulder comprising a shoulder top connected to the generally cylindrical neck opposite a shoulder bottom, a nose junction positioned around the shoulder bottom, a skirt connected circumferentially about the nose junction to extend away from the shoulder bottom, wherein the nose junction and the skirt are adapted to mate to a base junction in a cartridge.

The present invention provides a polymeric ammunition cartridge having polymer cartridge with a metal primer insert having a primer recess and a primer diffuser cup or ring inserted into the primer recess.

The present invention provides a polymeric ammunition cartridge having polymer cartridge with a metal primer insert having a primer recess and a primer diffuser cup or ring inserted into the primer recess.

The present invention provides a polymer nose for a polymeric ammunition cartridge having a generally cylindrical neck having a projectile aperture at a first end, a shoulder comprising a shoulder top connected to the generally cylindrical neck opposite a shoulder bottom, a nose junction positioned around the shoulder bottom, a skirt connected circumferentially about the nose junction to extend away from the shoulder bottom, wherein the nose junction and the skirt are adapted to mate to a base junction in a cartridge.

The present invention provides a method of making a two piece primer insert comprising: an upper primer insert portion comprising an upper primer bottom surface, an upper primer aperture through the upper primer bottom surface; a substantially cylindrical coupling element extending away from the upper primer bottom surface, and an interior surface; a lower primer insert portion comprising a lower primer bottom surface opposite a lower primer top surface having a primer recess, a lower primer aperture through the lower primer bottom surface, and a flange adapted to receive a polymer overmolding that extends circumferentially about an outer edge of the lower primer top surface; and an insert joint that links and aligns the upper primer bottom surface and the lower primer bottom surface to form a primer insert.

A system for firing reduced energy cartridges from a modern sporting rifle utilizes a bolt assembly weighing less than a conventional bolt assembly for such rifles and utilizes blow back for cycling the bolt assembly rather than gas operation. A bolt insert in a polymer bolt carrier of the bolt assembly has a projection that fits within a recess on the rear face of reduced energy cartridges. The reduced energy cartridges having a polymer casing, a rimfire power load for propellant, the power load recessed from the rear face of the casing. Tuning the bolt may comprise adjusting the weight of the bolt or the sliding resistance of the bolt assembly in the upper receiver. The bolt may be formed by metal injection molding with a polymer bolt carrier attached thereto.

The present invention provides a polymer nose for a polymeric ammunition cartridge having a generally cylindrical neck having a projectile aperture at a first end, an outer shoulder surface that extends from the generally cylindrical neck, an outer shoulder angle defined by the outer shoulder surface, an inner shoulder surface on the inside of the polymer nose opposite the outer shoulder surface, an inner shoulder angle defined by the outer shoulder surface, a skirt surface extending from the inner shoulder surface, a skirt angle defined by the skirt surface and a nose junction that extends from the outer shoulder surface to the skirt surface, wherein the nose junction is adapted to mate to a polymer cartridge.