THIN WALLED, TWO COMPONENT CARTRIDGE CASING

Abstract

A cartridge or ammunition casing is made of two components, one forming the outer casing sleeve and head end and the other comprising a plug seated within the head end to protect the outer casing material from propellant gases. The outer cylindrical sidewall and end panel of the casing may be made of a material selected from the group consisting of stainless steel, steel, pre-coated carbon steel, brass or brass-type alloys, aluminum, hardened aluminum alloys, and suitable polymeric plastic material such as nylon derivatives and VECTRA™. The inner plug may be made of a material selected from the group consisting of aluminum, brass, steel, stainless steel, and suitable polymeric materials.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional side view of a prior art 5.56 mm cartridge case.

FIG. 2 is a cross sectional side view of one embodiment of the cartridge case of the current invention.

FIG. 3 is a cross sectional side view of a cup used as the initial member in the production of the cartridge case of FIG. 2 in one embodiment.

FIG. 4 is a cross-sectional side view of the cup of FIG. 3 after the formation of the primer pocket and part of the extractor groove.

FIG. 5 is a cross-sectional side view of a reinforcing plug.

FIG. 5A is a cross sectional side view of an alternate embodiment of the plug of FIG. 5 having a small rim its base end.

FIG. 5B is a cross sectional side view of another alternate embodiment of a plug of FIG. 5 having a circumferential recess.

FIG. 6 is a cross sectional side view of the cup of FIG. 4 which is being expanded with an expansion punch and supporting die.

FIG. 7 is a cross sectional side view of the case sleeve of FIG. 6 with the reinforcing plug in place.

FIG. 8 is a cross sectional side view of a cartridge using the cartridge case of the invention as depicted in FIG. 1.

FIG. 8A is a cross-sectional side view of a rimless cartridge using a reinforcing sheet rather than the reinforcing plug of FIG. 8.

FIG. 8B is a cross-sectional side view of a rimmed cartridge using a reinforcing sheet rather than the reinforcing plug of FIG. 8.

FIG. 8C is a cross-sectional side view of a rimmed cartridge using the reinforcing plug as depicted in FIG. 5A.

FIG. 8D is a cross-sectional side view of a rimmed cartridge using a reinforcing plug that has no rim and wherein the outer rim is provided entirely by the case sleeve.

FIG. 8E is a cross-sectional side view of a rimless cartridge using a reinforcing plug as depicted in FIG. 5B, wherein the case wall is depressed into the plug's annular recess.

FIG. 9 depicts a cartridge using the cartridge case of the current invention which is chambered within a firearm.

Claims

1. A casing for cartridge ammunition, the casing having a head end and an interior volume for containing propellant comprising: a) a generally cylindrical sleeve portion that forms the sidewall of the casing with a casing sidewall inner surface, the casing being further substantially closed at the head end by a casing end panel having a circumferential boundary joined with the sidewall, the casing end panel having a centrally located end panel opening to receive a primer, andb) an inner reinforcing plug seated against the head end to provide support to the casing against the high pressures experienced in the firing of the ammunition, the inner plug having a primer recess formed therein and aligned with said end panel opening to receive a primer, the recess being provided with one or more perforations through the inner plug to permit gas from the primer to enter into the interior of the casing

2. The casing as in claim 1 wherein the inner plug is a solid body which extends laterally between the primer recess and the casing sidewall where the plug is fitted to bear against the inner surface of the casing sidewall to seal-off the casing sidewall and casing end panel from propellant gas arising up on firing of the ammunition.

3. The casing as in claim 1 wherein the casing end panel is provided with an inwardly depressed, cup-shaped primer pocket defining a primer well fitted into the primer recess in the plug, the primer well having a cylindrical sidewall connected to the casing end panel at the head end and formed therein to accept a primer, the primer well having a seating surface for the primer in the form of an annular base that closes-off the inner end of the cylindrical wall of the primer well, the primer pocket having a perforation there through aligned with or in communication with the one or more perforations in the inner plug to allow the primer gases to ignite propellant within the inner volume of the casing upon firing.

4. The casing as in any one of claims 1, 2 or 3 wherein said outwardly-directed cylindrical plug surface extends forwardly towards the open end of the casing, past the depth of the primer recess.

5. The casing as in claim 4 wherein the inner plug comprises an outer cylindrical extension in the form of a flange that is positioned to extend upwardly towards the open end of the casing forwardly beyond the depth of the primer recess while lying sealingly against the inner surface of the casing sidewall.

6. The casing as in claim 5 wherein the material forming such a flange is of a dimension and of a material sufficiently ductile to engage intimately with the casing sidewall and ensure the seal between the plug and the casing sidewall under the pressure of expanding propellant gases.

7. The casing as in claim 6 wherein the flange tapers with reducing thickness as it extends towards the forward end of the casing.

8. The casing as in claim 1 wherein the inner plug is in the form of a layer which provides the primer pocket which defines the primer well, and conforms to the inner face of the end panel and an initial portion of the inner surface of the casing sidewall to seal-off the casing sidewall and casing and panel from propellant gas arising upon firing of the ammunition.

9. The casing as in claim 1 wherein the casing end panel is joined seamlessly in a unitary manner to the casing sidewall around the circumferential boundary of the casing end.

10. The casing as in claim 9 wherein the outer casing sidewall and outer casing end panel are all formed from one piece of common material.

11. The casing as in claim 10 wherein the thickness of the casing sidewall is equal to or greater than the thickness of the casing and wall panel.

12. The casing as in claim 10 wherein the outer casing sidewall and end panel are of nearly the same relatively constant thickness.

13. The casing as in claim 1 wherein the plug engages with the inner surface of the casing sidewall through an interference fit.

14. The casing as in claim 1 wherein to keep the plug in place within the casing, the casing sidewall is provided with a slight inward taper towards its forward end, forward of the plug.

15. The casing as in claim 3 wherein the inner plug is in the form of a sheet shaped to fit over and embrace the primer well, extending to and along the inside surface of the casing end panel at the head end, and extending upwardly along the casing sidewall in the form of an outer a cylindrical extension of the sheet to seal-off the casing sidewall and casing and panel from propellant gas arising upon firing of the ammunition.

16. The casing as in claim 3 wherein the plug embraces the cylindrical sidewall of the primer well around its outside surface strengthening the primer well against expansion when the primer is pressed therein and helping to retain the primer in the primer well by a friction fit.

17. The casing as in claim 1 wherein, to provide rimmed ammunition, the casing sidewall, at its juncture with the circumferential boundary of the end panel, extends outwardly to provide that the diameter of the end panel is greater than the diameter of the cylinder defined by the casing sidewall to form a protruding annular rim to provide an extraction rim for the casing.

18. The casing as in claim 1 wherein, to provide rimless ammunition with an extractor groove formed therein adjacent to the head end, the inner plug has an annular groove, step or recess formed therein to provide a space and the casing wall overlying the groove, step or recess in the plug is deformed to fit within such space to provide an extraction groove for the casing.

19. The casing as in claim 18 wherein the plug has upper and lower portions with a straight-footed cylindrical support in its lower portion that extends to the inside surface of the end panel at the head end of the casing, the diameter of the cylindrical foot being reduced from the main diameter of the upper portion of the plug to provide room for the formation of the extraction groove in the sidewall of the casing.

20. The casing as in claim 19 wherein the plug comprises a plug-rim at the head end portion of the cylindrical foot and wherein the outer casing sidewall is rolled or crimped over this plug-rim to lock the plug in place and to form an extraction rim.

21. The casing as in any one of claims 17 or 20 wherein the rim is bent slightly forwardly so that it protrudes at less than a right angle from the casing sidewall to better engage with the extractor mechanism of a weapon.

22. The casing as in claim 1 wherein the outer cylindrical sidewall and end panel of the casing are made of the material selected from the group consisting of stainless steel, steel, pre-coated carbon steel, brass or brass-type alloys, aluminum, hardened aluminum alloys, and suitable polymeric plastic material such as nylon derivatives and VECTRA™.

23. The casing as in claim 1 wherein the outer cylindrical sidewall, end panel of the casing and primer well are made exclusively of polymeric material.

24. The casing as in any one of claims 22 or 23 wherein the inner plug is made of the material selected from the group consisting of aluminum, brass, steel, stainless steel, and suitable polymeric materials.

25. A method of manufacturing a casing as in claim 1 wherein the inner plug has upper and lower portions and outer circumferential sidewall surfaces with upper and lower portions and an annular indentation to serve as a plug groove is formed in the lower portion of plug, comprising the steps of: 1) providing an outer cylindrical tube with a sidewall to form the eventual casing sidewall, the tube being closed at one end to provide the casing end panel;2) inserting the plug into the base end of the casing sleeve portion3) pressing the tube sidewall into the annular indentation to provide an extractor groove for the casing.

26. A method of manufacturing a casing as in claim 1 wherein the inner plug has upper and lower portions and outer circumferential sidewall surfaces with upper and lower portions and an annular indentation formed in the lower portion of plug, terminating in an outwardly extending plug annular rim, comprising the steps of: 1) providing an outer cylindrical tube with a sidewall to form the eventual casing sidewall, the tube being closed at one end to provide the casing end panel and having a diameter which is larger than the casing sidewall diameter;2) inserting the plug into the base end of the casing sleeve portion;3) pressing the tube sidewall over the plug annular rim to provide a rim for the casing, and4) reforming the diameter of the cylindrical tube above the rim to the diameter of the casing sidewall.

27. A method of manufacturing a casing as in claim 1 wherein the inner plug has upper and lower portions and outer circumferential sidewall surfaces with upper and lower portions and an annular indentation formed in the lower portion of plug, comprising the steps of: 1) providing an outer cylindrical tube with a sidewall to form the eventual casing sidewall, the tube being closed at one end to provide the casing end panel and having a diameter which is smaller than the eventual casing sidewall diameter;2) forming an outwardly extending casing rim at the closed end of the cylindrical tube, the rim having the diameter of the eventual casing sidewall;3) expanding a portion of the tube sidewall commencing at a point above the end panel sufficient to provide an extractor groove for the casing and a casing sidewall of a final diameter for the casing; and4) inserting the plug into the base end of the casing sleeve portion.

28. A method of manufacturing a casing for cartridge ammunition, the casing having a cylindrical casing sidewall of final diameter and a head end closed by an end panel comprising the steps of: 1) providing an outer cylindrical tube with a sidewall to form the eventual casing sidewall, the tube being closed at one end to provide the casing end panel and having a diameter which is smaller than the eventual, final, casing sidewall diameter;2) forming in outwardly extending casing rim at the closed end of the cylindrical tube, the rim having the diameter of the eventual casing sidewall; and3) expanding a portion the tube sidewall commencing at a point above the end panel sufficient to provide an extractor groove for the casing and a casing sidewall of the final diameter for the casing.