Jacketed boat-tail bullet

• US 7,918,164 B1
• Filed: 12/19/2006
• Issued: 04/05/2011
• Est. Priority Date: 04/26/2004
• Status: Active Grant

• Current Assignee: OLIN Corporation
• Original Assignee: OLIN Corporation
• Inventors: Eberhart, Gerald Todd
• Primary Examiner(s): Bergin; James S
• Application Number:
  US11/642,050
• Publication Number:
  US 20110088537A1
• Time in Patent Office: 1,568 Days
• Field of Search: 102/501, 102/514, 102/515, 102/516, 102/517, 102/518, 102/519, 86/54, 86/55, 86/51
• US Class Current: 102/516
• CPC Class Codes: F42B 12/74 of the core or solid body
• CPC Class Codes: F42B 12/78 of jackets for smallarm bullets ; Jacketed bullets or projectiles

Abstract

A bullet includes at least a mid core and a rear core in tandem alignment. The hardness of the mid core is greater than the hardness of the rear core. A jacket envelops both the mid core and the rear core. The jacket has a generally cylindrical sidewall, which is in contact with the mid core, and a boat-tail, which is in contact with the rear core. The rear core is substantially contained within the boat-tail. The mid core and the rear core may be substantially lead-free. In one embodiment, the bullet includes a front core in tandem alignment with the rear core and in contact with a nose portion of the jacket. In another embodiment, the mid core extends from the nose portion of the bullet to the boat-tail.

Claims

1. A method for making a bullet, the method comprising:

forming a jacket precursor to include;

a nose portion, and

a generally cylindrical sidewall extending from the nose portion, the nose portion and the generally cylindrical sidewall defining a cavity;

depositing at least a one-piece mid core that includes a substantially monolithic, non-tubular construction within the cavity;

depositing a rear core within the cavity in tandem alignment with the mid core and positioned proximate a rear portion of the cylindrical sidewall, the rear core having a hardness less than the hardness of the mid core; and

angularly indenting the rear portion of the cylindrical sidewall and the rear core to form a boat-tail, wherein after the indenting, the rear core substantially fills the boat-tail.

2. The method of claim 1, wherein the mid core and the rear core are substantially lead-free.

3. The method of claim 1, wherein after the indenting, the mid core extends from the nose portion to the boat-tail.

4. The method of claim 3, wherein the mid core has a weight of about 38 grains and is formed from:

a high-density constituent material selected from the group of tungsten, tungsten carbide, carballoy, and ferro-tungsten, and

a second, lower-density constituent consisting of either a metallic matrix material or a plastic matrix material; and

wherein the rear core has a weight of about 4.3 grains and is formed from tin or a tin base alloy.

5. The method of claim 1, further comprising:

depositing a front core within the cavity in tandem alignment with the mid core, the front core being positioned adjacent to the nose portion.

6. The method of claim 5, wherein the front core is formed from steel.

7. The method of claim 6, wherein the mid core has a weight of about 30 grains and is formed from:

a high-density constituent material selected from the group of tungsten, tungsten carbide, carballoy, and ferro-tungsten, and

a second, lower-density constituent consisting of either a metallic matrix material or a plastic matrix material; and

wherein the rear core has a weight of about 4.3 grains and is formed from tin or a tin base alloy.

8. The method of claim 1, wherein the mid core is formed from:

a high-density constituent material selected from the group of tungsten, tungsten carbide, carballoy, and ferro-tungsten; and

a second, lower density constituent consisting of either a metallic matrix material or a plastic matrix material.

9. The method of claim 8, wherein the metallic matrix material is selected from the group consisting of:

tin, zinc, iron, copper, and mixtures or alloys of one or more of the foregoing.

10. The method of claim 8, wherein the plastic matrix material is selected from the group consisting of:

phenolics, epoxies, dialphthalates, acrylics, polystyrenes, polyethylene, or polyurethanes.

11. The method of claim 1, wherein the mid core is formed from one of:

copper, bismuth, tin, gold, silver, pewter, bronze and mixtures or alloys including one or more of the foregoing.

12. The method of claim 1, wherein the mid core is formed from an organic polymer filled with a metal.

13. The method of claim 1, wherein the rear core has a Brinell hardness less than about 50.

14. The method of claim 13, wherein the rear core is formed from tin or a tin base alloy.

15. The method of claim 13, wherein the rear core is formed from one of:

copper, zinc, tin, and mixtures or alloys including one or more of the foregoing.

16. The method of claim 1, wherein a transition point between the generally cylindrical sidewall and the boat-tail is formed by a rebate in the generally cylindrical sidewall.

17. The method of claim 1 wherein the rear core is inserted into the jacket in the form of a sphere.

18. A method for making a bullet, the method comprising:

forming a jacket precursor to include;

a nose portion, and a generally cylindrical sidewall extending from the nose portion, the nose portion and the generally cylindrical sidewall defining a cavity;

depositing at least one forward core of substantially monolithic, non-tubular construction and a rear core into the cavity, the rear core being in tandem alignment with the at least one forward core and positioned proximate a rear portion of the cylindrical sidewall, the rear core having a hardness less than the hardness of the at least one forward core; and

angularly indenting the rear portion of the cylindrical sidewall and the rear core to form a boat-tail, wherein after the indenting, the rear core substantially fills the boat-tail.