REINFORCED LIGHTWEIGHT CARTRIDGE

• US 3,797,396 A
• Filed: 03/15/1972
• Issued: 03/19/1974
• Est. Priority Date: 03/15/1972
• Status: Expired due to Term

• Current Assignee: Frederick P. Reed
• Original Assignee: Frederick P. Reed
• Inventors: Reed, Frederick P.
• Primary Examiner(s): Stahl, Robert F.
• Application Number:
  US05/234,731
• Time in Patent Office: 734 Days
• Field of Search: 102/43R,43P,44,38,42R
• US Class Current: 102/468
• CPC Class Codes: F42B 5/285 formed by assembling several elements

Abstract

The firing obturation of lightweight military cartridges fabricated from a material other than brass can be considerably improved by the inclusion of a thin-walled cup in the head portion of the case prior to forming the required exterior taper thereof. Since the cup is fabricated from a more deformable material than that of the case, the tapering of the latter produces radial recovery forces in the mouth of the cup which serve to increase the total pressure imparted to the cartridge case sidewalls by the pressures generated during the firing of the cartridge thereby accelerating the obturation of the case in the firing chamber to a greater degree along the portion coextensive with the cup mouth than along the remainder of the case.

Claims

1. In a firearm cartridge having a forwardly tapered case of a material other than brass adapted to expand into obturating contact with the interior walls of a firing chamber in response to the gas pressures generated during the firing of the cartridge, the improvement of, a substantially cylindrical reinforcing cup of a more deformable material than that of said case and disposed within the rearward half thereof, said cup having the exteriOr periphery thereof in forwardly increasing compressive engagement with the forwardly tapered interior surface of said case to form an interference fit therebetween, said cup also having forwardly increasing radial recovery forces therein which approach a maximum at the forward end thereof to impart corresponding obturating expansion to the portion of said case coextensive with said cup.

2. The cartridge structure defined in claim 1 wherein said case is formed of steel and said cup is formed of brass.

3. The cartridge structure defined in claim 1 wherein said case is formed of a heat treated aluminum alloy and said cup is formed of a more ductile untreated aluminum alloy.

4. The catridge structure defined in claim 1 wherein said case is formed of aluminum and said cup is formed of a thermosetting resin.

5. The cartridge structure defined in claim 1 wherein said reinforcing cup is formed with an open end of slightly larger diameter than the opposite closed end thereof to induce a maximum amount of recovery forces therein subsequent to the forming of the forward taper required by the case.

6. In a firearm cartridge having a case of deformable material other than brass adapted to expand into obturating contact with the interior wall surface of a firing chamber in response to the pressures generated during the firing of the cartridge, said case comprising, a head, a hollow body extending forwardly from said head to define a forwardly tapered interior, and a reinforcing cup of a more deformable material than that of said case disposed within the rearward half of said body and having an original exterior periphery of greater diameter than the corresponding interior diameter of said hollow body prior to the tapering thereof to define an interference fit therebetween, said cup also having radial recovery forces therein increasing forwardly along the length thereof to impart a maximum rapidity of obturating expansion to said case in the vicinity of the forward end of said cup.

7. The cartridge defined in claim 6 wherein said head and said body of said case are formed of aluminum and said cup is formed of a thermosetting epoxy resin of sufficient thickness and resiliency to obturate any rupture which may occur within the portion of said body contiguous with said cup during the firing of the cartridge.