PLASTIC CARTRIDGE CASE

• US 3,745,924 A
• Filed: 03/30/1970
• Issued: 07/17/1973
• Est. Priority Date: 03/30/1970
• Status: Expired due to Term

• Current Assignee: John J. Scanlon
• Original Assignee: John J. Scanlon
• Inventors: Scanlon, John J.
• Primary Examiner(s): Stahl, Robert F.
• Application Number:
  US05/023,861
• Time in Patent Office: 1,205 Days
• Field of Search: 102/38,43,43P,43F,42
• US Class Current: 102/467
• CPC Class Codes: F42B 5/307 formed by assembling several elements
• CPC Class Codes: F42B 5/36 modified for housing an integral firing-cap

Abstract

A plastic cartridge whose ballistics are equivalent to existing metallic cartridges and which can be fired in existing firearms. A non-expanding metal head is securely attached to the breech end of the plastic casing by compressively squeezing the rear end of the plastic casing between a metal head and a second metallic member, either an annular support member plus a primer or by the primer itself. The plastic casing is preferably formed by drawing at least the front end of the casing and then necking down the mouth portion. The preferable plastic materials for cartridge casings include polycarbonates, polysulfones, and blends of plastics, e. g. a blend of polyethylene and polycarbonate, a blend of polyethylene and polysulfones, and alloys of polysulfones and polycarbonates.

Claims

2. A cartridge as recited in claim 1 in which said metal head is made of hardened steel having a hardness ranging from about RC45 to about RC50.

3. A cartridge as recited in claim 2 wherein at least the forward mouth end of the tubular body portion has been cold worked in order to decrease the thickness of the tubular body wall and increase the strength characteristics of the forward mouth end, said forward mouth end being necked down to a smaller diameter in order to accommodate a single projectile.

4. A cartridge having a drawn plastic cartridge casing, said casing comprising a tubular body portion having a front mouth end and a rear breech end, said front mouth end being necked down to form a smaller-diameter mouth portion in which a single projectile means is positioned, a transverse wall portion integral with said tubular body portion and located adjacent to but spaced from the breech end of the casing, an annular ring means integral with and projecting rearwardly from said transverse wall portion, said ring means being held in compreSsion by an outer rigid metallic head member and a separate inner flexible metallic member.

5. A cartridge as recited in claim 4 in which said necked-down mouth portion has been cold worked more than any other portion of the plastic cartridge casing and thus has improved strength properties over the remaining portions of the casing.

6. A cartridge as recited in claim 5 wherein said outer metallic head is made of material which is substantially unyielding under the intended pressure and said inner metallic member is made of material which is rigid enough to co-operate with the rigid head to put the annular plastic ring in compression but still flexible enough to permit the inner member to expand outwardly against the annular plastic ring upon firing to act as a gas seal therewith.

7. A cartridge having a drawn plastic casing, said casing having a tubular body portion and a front mouth portion which has been elongated in an axial direction as well as expanded outwardly so as to decrease the wall thickness of the body at the mouth end thereof, and to provide additional strength thereto, said mouth portion being necked down to provide an opening which is of lesser diameter than said tubular body portion, a single projectile secured in said mouth opening, said plastic casing being made of a thermoplastic material selected from the group of plastics and blends of plastics having high impact strength, dimensional stability, high flexural modulus, and high deflection temperature, consisting of polycarbonates, polysulfone, blends of minor portions of polyethylene with polycarbonates, blends of minor portions of polyethylene with polysulfone, and alloys of polysulfones and polycarbonates