Subsonic small-caliber ammunition and bullet used in same

• US 20110290141A1
• Filed: 05/25/2010
• Published: 12/01/2011
• Est. Priority Date: 05/25/2010
• Status: Abandoned Application

• Current Assignee: Engel Ballistic Research
• Original Assignee: Engel Ballistic Research
• Inventors: Backman, Phil, Luchini, Christopher Bernard, Engel, John Whitworth
• Application Number:
  US12/800,879
• Publication Number:
  US 20110290141A1
• Time in Patent Office: Days
• US Class Current: 102/439
• 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
• CPC Class Codes: F42B 30/02 Bullets
• CPC Class Codes: F42B 5/16 characterised by composition or physical dimensions or form of propellant charge, with or without projectile, or powder chemical composition C06B; F42B5/24 takes precedence

Abstract

A bullet for use with a small caliber rifle comprises a jacket and a lead core provided within the jacket. The jacket is drawn from a copper alloy material. A bearing surface portion of the jacket has a nominal thickness less than about .010″ and the copper alloy material of at least the bearing surface portion of the jacket has a nominal hardness that is substantially greater than an as-drawn hardness of the copper alloy material of the bearing surface portion of the jacket.

Claims

1. A bullet for use with a small caliber rifle, comprising:

a jacket drawn from a copper alloy material, wherein a bearing surface portion of the jacket has a nominal thickness less than about 0.010″ and

wherein the copper alloy material of at least the bearing surface portion of the jacket has a nominal hardness that is substantially greater than an as-drawn hardness of the copper alloy material of the bearing surface portion of the jacket; and

a lead core provided within the jacket.

2. The bullet of claim 1 wherein the bearing surface portion of the jacket is at least partially coated with a friction-reducing material composition.

3. The bullet of claim 2 wherein the friction-reducing material composition is molybdenum disulfide.

4. The bullet of claim 3 wherein the bearing surface portion is coated in its entirety with the friction-reducing material composition.

5. The bullet of claim 1 wherein the nominal hardness of the copper alloy material of at least bearing surface portion corresponds to a tensile strength of between about 32 ksi and about 44 ksi.

6. The bullet of claim 5 wherein the bearing surface portion of the jacket is at least partially coated with a friction-reducing material composition.

7. The bullet of claim 6 wherein the friction-reducing material composition is molybdenum disulfide.

8. The bullet of claim 7 wherein the bearing surface portion is coated in its entirety with the friction-reducing material composition.

9. The bullet of claim 5 wherein the bearing surface portion of the jacket has a thickness between about 0.004″

and about 0.008″

.

10. The bullet of claim 1 wherein the bearing surface portion of the jacket has a thickness between about 0.004″

and about 0.008″

.

11. A round of ammunition configured for providing sufficient energy for cycling a bolt carrier in a rifle having a gas-energized bolt carrier actuation mechanism, comprising:

a small-caliber cartridge casing configured in accordance with an original equipment manufacturer (OEM) specification for the rifle;

a bullet having a bearing surface portion thereof engaged within a bullet receiving opening of the small-caliber cartridge casing thereby forming a propellant-receiving cavity within the small-caliber cartridge casing, wherein the bullet has a core made of a metal having lead as its major constituent component and a jacket drawn from metal having copper as its major constituent component, wherein a nominal thickness of the jacket is less than about 0.010″

, and wherein at least the bearing surface portion of the jacket has a nominal hardness that is substantially greater than an as-drawn hardness of the jacket; and

a propellant within the propellant-receiving cavity of the small-caliber cartridge casing, wherein the propellant is configured by a manufacturer thereof for being used in medium caliber ammunition.

12. The round of ammunition of claim 11 wherein the bearing surface portion of the jacket is at least partially coated with a friction-reducing material composition

13. The round of ammunition of claim 12 wherein the friction-reducing material composition is molybdenum disulfide.

14. The round of ammunition of claim 13 wherein the bearing surface portion is coated in its entirety with the friction-reducing material composition.

15. The round of ammunition of claim 11 wherein the nominal hardness of said jacket metal of at least the bearing surface portion corresponds to a tensile strength of between about 32 ksi and about 44 ksi.

16. The round of ammunition of claim 15 wherein the bearing surface portion of the jacket is at least partially coated with a friction-reducing material composition.

17. The round of ammunition of claim 16 wherein the friction-reducing material composition is molybdenum disulfide.

18. The round of ammunition of claim 17 wherein the bearing surface portion is coated in its entirety with the friction-reducing material composition.

19. The round of ammunition of claim 15 wherein the bearing surface portion of the jacket has a thickness between about 0.004″

and about 0.008″

.

20. The round of ammunition of claim 11 wherein the bearing surface portion of the jacket has a thickness between about 0.004″

and about 0.008″

.

21. A method for making a bullet for use with a small caliber rifle, comprising:

providing a jacket having a thickness less than about 0.010″

, wherein the jacket is drawn from a copper alloy material;

forming a lead core within a core-receiving cavity of the jacket; and

hardening at least a bearing surface portion of the jacket to have a nominal hardness that is substantially greater than an as-drawn hardness of the jacket after forming the lead core within the core-receiving cavity of the jacket.

22. The method of claim 21 wherein said hardening includes shot peening the jacket with steel shot.

23. The method of claim 22, further comprising:

exposing the jacket and the steel shot to a friction-reducing material composition during said shot peening such that said shot peening causes at least a portion of an exterior surface of the jacket to become coated with a layer of the friction-reducing material composition.

24. The method of claim 23 wherein the friction-reducing material composition is molybdenum disulfide.

25. The method of claim 21 wherein the nominal hardness of the copper alloy material of at least the bearing surface portion corresponds to a tensile strength of between about 32 ksi and about 44 ksi after performing said hardening.

26. The method of claim 25 wherein said hardening includes shot peening the jacket with steel shot.

27. The method of claim 26, further comprising:

exposing the jacket and the steel shot to a friction-reducing material composition during said shot peening such that said shot peening causes at least a portion of an exterior surface of the jacket to become coated with a layer of the friction-reducing material composition.