Jacketed one piece core ammunition
View Patent ↗A jacketed projectile having one-piece steel core provides good performance regarding chamber pressure, barrel wear and accuracy by separating the jacket from a central tapered portion of the core by providing an encircling air gap that facilitates engraving of the jacket during firing.
1. A jacketed projectile having front and rear ends separated by the length of the projectile and comprising:
a) an engravable jacket, and
b) a central core, the central core having a midsection portion which is not in continuous contact with the jacket over at least a portion of the midsection portion to allow engraving to occur on the jacket without full support from the core,
wherein the midsection portion is frusto-conical in shape and tapered, tapering towards only the front end of the projectile to provide a tapered separation between the jacket and the core along at least a portion of the length of the midsection portion to allow for progressive engraving of the jacket when the projectile is fired through a rifled barrel.
2. A jacketed projectile as in claim 1 comprising wherein the tapered separation provides a fully encircling gap between the jacket and the core along at least a portion of the length of the midsection portion of the core.
3. A projectile as in claim 2 wherein the encircling gap is in the form of a tapered gap present between the jacket is unsupported in the midsection portion along at least a portion of the length of the midsection portion, over the length of the separation.
4. A projectile as in claim 2 wherein the encircling gap is in the form of a fully encircling tapered gap present between the jacket and the full length of the midsection portion.
5. A projectile as in claim 2 wherein the gap is occupied by a compressible medium.
6. A projectile as in claim 5 wherein the compressible medium is air.
7. A projectile according to claim 1 wherein the half-conical angle of the frusto-conical portion of the core is between 0.7° and 1.0°.
8. A projectile according to claim 1 wherein the half-conical angle of the frustro-conical portion of the core is between 0.85° and 0.95°.
9. A projectile according to claim 1 comprising a short cylindrical portion of the core having an outer surface, the cylindrical portion extending rearwardly from the midsection of the core, wherein the jacket and outer surface of the cylindrical portion are in generally continuous contact with each other for the length of the cylindrical portion.
10. A projectile according to claim 9 wherein the cylindrical portion of the core is less than 30% of the length of the midsection portion.
11. A projectile as in claim 1 wherein the central core is principally composed of a material selected from the group consisting of carbon steel, tungsten, tungsten carbide, tungsten alloys, tungsten-nylon compounds, tungsten-tin compounds and mixtures thereof.
12. A projectile as in claim 11 wherein the central core has a hardness and the hardness of the central core is at least 45 on the Rockwell C hardness scale.
13. A projectile as in claim 1 wherein the core comprises a forward portion mounted ahead of the midsection, said forward portion having an ogival shape over at least a portion of its surface and wherein the junction between the forward and the midsection portions provides a relatively smooth transition zone.
14. A projectile as in claim 13 comprising an inwardly tapering end portion of the core positioned rearwardly of the cylindrical portion.
15. A projectile as in claim 14 wherein the rearwardly tapering end portion of the core has a half-conical angle of about 7 degrees.
16. A projectile as in claim 1 wherein the jacket material comprises gilding metal.
17. A projectile in accordance with claim 16 wherein the gilding metal jacket comprises approximately 90% copper and 10% zinc.
18. A projectile according to claim 17 wherein the gilding metal jacket has a thickness greater than a corresponding thickness of a jacket used on conventional ball projectiles of similar caliber.
19. A projectile according to claim 18 wherein the gilded metal jacket has a minimum thickness of 0.635 mm for a 5.56 mm ball round.