One embodiment of the present invention provides a polymeric ammunition cartridge and methods of making and using the same. The cartridge includes a substantially cylindrical insert connected to a substantially cylindrical polymeric middle body. The substantially cylindrical insert includes a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash hole positioned in the primer recess to extend through the bottom surface, and a flange that extends circumferentially about an outer edge of the top surface. The substantially cylindrical polymeric middle body includes a substantially cylindrical polymeric bullet-end and a substantially cylindrical polymeric coupling end connected by a powder chamber, wherein the substantially cylindrical polymeric coupling end extends over the substantially cylindrical coupling element and covers a circumferential surface of the primer flash hole.

A casing for an ammunition cartridge comprises a sleeve portion and a base portion. The casing may be two-piece, where the base portion is secured to the sleeve portion by means of a nipple having a flared end. The base portion comprises a cannelure that extends lengthwise from a flange. The cannelure, which is preferably curved, is deeper than a conventional cannelure and thus the casing weight is reduced. The cannelure has a step that is adjacent the flange, for limiting inward travel of the lip of a hook of the bolt of a firearm. Alternatively, a casing may be a one-piece casing, wherein the base and sleeve are integral.

The present invention provides a primer insert for use in a polymeric ammunition cartridge includes atop surface opposite a bottom surface and a extraction flange that extends circumferentially about an outer edge of the top surface; a coupling element that extends from the bottom surface, wherein the substantially cylindrical coupling element is adapted to receive a polymer overmolding; a primer recess in the top surface that extends toward the bottom surface, wherein the primer recess comprises a recess bottom and a circular recess side wall; a primer flash aperture through the recess bottom that extends through the bottom surface, wherein the primer flash aperture is adapted to receive a polymer overmolding to form a flash hole; and one or more pads positioned on the recess bottom; a groove in the primer recess positioned around the primer flash aperture to extend at least partially over the recess bottom and adapted to receive a polymer overmolding.

The present invention provides polymer ammunition having a primer insert having: a top surface; a bottom surface opposite the top surface; a coupling element that extends from the bottom surface, wherein the coupling element comprises an interior surface and an exterior surface, wherein the interior surface comprises: a transition region that transitions from the bottom surface to a second segment wherein the transition region has a radius of from 0.02 to 0.08; a first segment extending from the second segment and terminates at a tip, wherein the first segment has a first segment distance from 0.05 to 0.09 inches and the second segment has a second segment distance from 0.05 to 0.09 inches, wherein the second segment has a second segment angle from +3 to −3 degrees relative to the first segment angle and the first segment has a first segment angle from +6 to −6 degrees from perpendicular to the top surface; a primer recess in the top surface that extends toward the bottom surface; a primer flash aperture positioned in the primer recess through the bottom surface; and a flash aperture groove in the primer recess and positioned around the primer flash aperture and adapted to receive a polymer overmolding through the primer flash aperture.

The present invention provides an ammunition cartridge having a primer insert for having a top surface opposite a bottom surface and a extraction flange that extends circumferentially about an outer edge of the top surface; a coupling element that extends from the bottom surface, wherein the substantially cylindrical coupling element is adapted to receive a polymer overmolding; a primer recess in the top surface that extends toward the bottom surface, wherein the primer recess comprises a recess bottom and a circular recess side wall; a primer flash aperture through the recess bottom that extends through the bottom surface, wherein the primer flash aperture is adapted to receive a polymer overmolding to form a flash hole; and a groove in the primer recess positioned around the primer flash aperture adapted to receive a polymer overmolding, wherein the groove extends at least partially over the bottom surface and the groove is adapted to receive polymer at least partially over the bottom surface.

One embodiment of the present invention provides a polymeric ammunition cartridge and methods of making and using the same. The cartridge includes a substantially cylindrical insert connected to a substantially cylindrical polymeric middle body. The substantially cylindrical insert includes a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash hole positioned in the primer recess to extend through the bottom surface, and a flange that extends circumferentially about an outer edge of the top surface. The substantially cylindrical polymeric middle body includes a substantially cylindrical polymeric bullet-end and a substantially cylindrical polymeric coupling end connected by a powder chamber, wherein the substantially cylindrical polymeric coupling end extends over the substantially cylindrical coupling element and covers a circumferential surface of the primer flash hole.

The present invention provides a method of making a substantially cylindrical insert by metal injection molding by providing a primer insert injection mold to form a substantially cylindrical metal primer insert, injection molding the metal injection molding feedstock into the primer insert injection mold to form a first substantially cylindrical metal primer insert having a first size; debinding the first substantially cylindrical metal primer insert to remove the first binding agent; and sintering the first substantially cylindrical metal primer insert to remove the second binding agent and form the substantially cylindrical metal primer insert having a second size.

The present invention provides a polymer ammunition cartridge having a primer insert having: a top surface; a bottom surface opposite the top surface; a coupling element that extends from the bottom surface, wherein the coupling element comprises an interior surface and an exterior surface, wherein the interior surface comprises: a transition region that transitions from the bottom surface to a second segment wherein the transition region has a radius of from 0.02 to 0.2; a first segment extending from the second segment and terminates at a tip, wherein the first segment has a first segment distance from 0.02 to 0.18 inches and the second segment has a second segment distance from 0.02 to 0.18 inches, wherein the second segment has a second segment angle from +3 to −3 degrees relative to the first segment angle and the first segment has a first segment angle from +6 to −6 degrees from perpendicular to the top surface; a primer recess in the top surface that extends toward the bottom surface; a primer flash aperture positioned in the primer recess through the bottom surface; and a flash aperture groove in the primer recess and positioned around the primer flash aperture and adapted to receive a polymer overmolding through the primer flash aperture.

The present invention provides a primer insert for use in a polymeric ammunition cartridge includes a top surface opposite a bottom surface and a extraction flange that extends circumferentially about an outer edge of the top surface; a coupling element that extends from the bottom surface, wherein the substantially cylindrical coupling element is adapted to receive a polymer overmolding; a primer recess in the top surface that extends toward the bottom surface, wherein the primer recess comprises a recess bottom and a circular recess side wall; a primer flash aperture through the recess bottom that extends through the bottom surface, wherein the primer flash aperture is adapted to receive a polymer overmolding to form a flash hole; and a groove in the primer recess positioned around the primer flash aperture adapted to receive a polymer overmolding, wherein the groove extends at least partially over the bottom surface and the groove is adapted to receive polymer at least partially over the bottom surface

The present invention provides a primer insert for use in a polymeric ammunition cartridge includes a top surface opposite a bottom surface and a extraction flange that extends circumferentially about an outer edge of the top surface; a coupling element that extends from the bottom surface, wherein the substantially cylindrical coupling element is adapted to receive a polymer overmolding; a primer recess in the top surface that extends toward the bottom surface, wherein the primer recess comprises a recess bottom and a circular recess side wall; a primer flash aperture through the recess bottom that extends through the bottom surface, wherein the primer flash aperture is adapted to receive a polymer overmolding to form a flash hole; and a groove in the primer recess positioned around the primer flash aperture adapted to receive a polymer overmolding, wherein the groove extends at least partially over the bottom surface and at least partially over the circular recess side wall and the groove is adapted to receive polymer over the bottom surface and at least partially over the circular recess side wall.