US Patent 9927219 Primer insert for a polymer ammunition cartridge casing

The present invention includes a metal primer insert for a polymeric ammunition cartridge having 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 aperture 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, wherein the flange is adapted to receive a polymer overmolding that covers an circumferential surface and the primer flash aperture to form a primer flash hole.