Method of making a polymer ammunition cartridge casing
View Patent ↗One embodiment of the present invention provides methods of making a polymeric ammunition cartridge. 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.
1. A method of forming a polymeric ammunition cartridge comprising the steps of:
providing a substantially cylindrical primer insert comprising
a base having a top surface opposite a bottom surface;
a substantially cylindrical coupling flange that extends from the top surface forming a substantially cylindrical inner surface;
a substantially cylindrical primer wall that extends from the bottom surface wherein a substantially cylindrical primer recess is formed by the inner surface of the substantially cylindrical primer wall and a groove formed on the circumference of an outer surface of the substantially cylindrical primer wall;
wherein the substantially cylindrical inner surface is opposite the substantially cylindrical primer recess;
a primer aperture formed through the base to connect the substantially cylindrical inner surface to the substantially cylindrical primer recess; and
a flash hole groove formed about the primer aperture on the bottom surface; and
forming a substantially cylindrical polymeric middle body having the substantially cylindrical primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end by contacting a polymeric material with the substantially cylindrical primer insert, wherein the polymeric material covers the substantially cylindrical coupling flange and extends over the substantially cylindrical inner surface to the flash hole groove to form a primer flash hole and extends over the outer surface of the substantially cylindrical primer wall to the groove; wherein a propellant chamber extends from the substantially cylindrical polymeric coupling region to the primer flash hole;
providing a substantially cylindrical polymeric bullet-end comprising a substantially cylindrical polymeric coupling end opposite a bullet aperture; and
connecting the substantially cylindrical polymeric coupling region to the substantially cylindrical polymeric coupling end to form a propellant chamber from the bullet aperture to the primer flash hole.
2. The method of claim 1 , wherein the substantially cylindrical polymeric bullet-end comprises a shoulder positioned between the substantially cylindrical polymeric coupling end and the bullet aperture.
3. The method of claim 1 , wherein the bullet aperture further comprises a cantilever ring.
4. The method of claim 1 , further comprising the step of inserting a primer into the substantially cylindrical primer recess.
5. The method of claim 1 , further comprising the step of providing a diffuser ring having a diffuser ring aperture with a lip that extends at least partially into the primer flash hole.
6. The method of claim 1 , further comprising the step of providing a diffuser ring having a diffuser ring aperture with a lip that extends through the primer flash hole.