Two-piece primer insert for polymer ammunition

1. A two piece primer insert for ammunition comprising:

an upper primer insert portion connected to a lower primer insert portion, wherein the upper primer insert portion comprises

an upper primer bottom surface and an upper primer top surface opposite the upper primer bottom surface,

an upper primer aperture through the upper primer bottom top surface,

a substantially cylindrical coupling element extending away from the upper primer bottom surface,

wherein the lower primer insert comprises:

a lower primer top surface opposite a lower primer bottom surface,

a primer recess in the lower primer top surface that extends toward the lower primer bottom surface and adapted to fit a primer,

a lower flash hole aperture through the lower primer bottom surface extending to the primer recess; and

a flash hole groove in the top surface of the upper primer insert portion, the flash hole groove extends circumferentially about the upper primer aperture and the flash hole groove is larger than the upper primer aperture and the lower flash hole aperture, and wherein the flash hole groove is configured to receive a polymer overmolding through the upper primer aperture and the flash hole groove is between the upper primer aperture and the lower flash hole aperture.

2. The two piece primer insert of claim 1 , wherein the upper primer insert portion and the lower primer insert portion form an insert joint that is threaded, riveted, locked, friction fitted, coined, snap fitted, chemical bonded, chemical welded, soldered, smelted, sintered, adhesive bonded, laser welded, ultrasonic welded, friction spot welded, or friction stir welded.

3. The two piece primer insert of claim 1 , wherein the upper primer insert portion, the lower primer insert portion or both are formed independently by metal injection molding, polymer injection molding, stamping, milling, molding, machining, punching, fine blanking, smelting, or any other method that will form insert portions that may be joined together to form a primer insert.

4. The two piece primer insert of claim 1 , wherein the upper primer insert portion, the lower primer insert portion or both independently comprises a polymer, a metal, an alloy, or a ceramic alloy.

5. The two piece primer insert of claim 4 , wherein the upper primer insert portion and the lower primer insert portion comprise of the same material or different materials.

6. The two piece primer insert of claim 1 , wherein the upper primer insert portion and the lower primer insert portion comprise different polymers, different metals, different alloys, or different ceramic compositions.

7. The two piece primer insert of claim 1 , wherein the upper primer insert portion comprises a polymer, a metal, an alloy, or a ceramic alloy and the lower primer insert portion comprises different polymer, metal, alloy, or ceramic alloy.

8. The two piece primer insert of claim 1 , wherein the upper primer insert portion and the lower primer insert portion independently comprise steel, nickel, chromium, copper, carbon, iron, stainless steel or brass.

9. The two piece primer insert of claim 1 , wherein the upper primer insert portion comprises 102, 174, 201, 202, 300, 302, 303, 304, 308, 309, 316, 316L, 316Ti, 321, 405, 408, 409, 410, 415, 416, 416R, 420, 430, 439, 440, 446 or 601-665 grade stainless steel or Ti 6 Al 4 V and the lower primer insert portion comprises 102, 174, 201, 202, 300, 302, 303, 304, 308, 309, 316, 316L, 316Ti, 321, 405, 408, 409, 410, 415, 416, 416R, 420, 430, 439, 440, 446 or 601-665 grade stainless steel or Ti 6 Al 4 V.

10. The two piece primer insert of claim 1 , wherein the upper primer insert portion and the lower primer insert portion independently comprises:

(a) 2-16% Ni; 10-20% Cr; 0-5% Mo; 0-0.6% C; 0-6.0% Cu; 0-0.5% Nb+Ta; 0-4.0% Mn; 0-2.0% Si and the balance Fe;

(b) 2-6% Ni; 13.5-19.5% Cr; 0-0.10% C; 1-7.0% Cu; 0.05-0.65% Nb+Ta; 0-3.0% Mn; 0-3.0% Si and the balance Fe;

(c) 3-5% Ni; 15.5-17.5% Cr; 0-0.07% C; 3-5.0% Cu; 0.15-0.45% Nb+Ta; 0-1.0% Mn; 0-1.0% Si and the balance Fe;

(d) 10-14% Ni; 16-18% Cr; 2-3% Mo; 0-0.03% C; 0-2% Mn; 0-1% Si and the balance Fe;

(e) 12-14% Cr; 0.15-0.4% C; 0-1% Mn; 0-1% Si and the balance Fe;

(f) 16-18% Cr; 0-0.05% C; 0-1% Mn; 0-1% Si and the balance Fe;

(g) 3-12% aluminum, 2-8% vanadium, 0.1-0.75% iron, 0.1-0.5% oxygen, and the remainder titanium; or

(h) 6% aluminum, about 4% vanadium, about 0.25% iron, about 0.2% oxygen, and the remainder titanium.