Multi-Piece Polymer Ammunition Cartridge

Abstract

The present invention provides a molded polymer ammunition, ammunition cartridge, ammunition case, and ammunition mid-case, that is overmolded over a primer insert and into a flash aperture of the primer insert fitted to a polymer nose to be used to make polymer ammunition.

What is claimed is: 
     
         1 . A polymeric ammunition cartridge comprising:
 a substantially cylindrical insert comprising   a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface,   a primer recess in the top surface that extends toward the bottom surface,   a primer flash hole positioned in the primer recess to extend through the bottom surface, and   a flange that extends circumferentially about an outer edge of the top surface; and   a substantially cylindrical polymeric middle body comprising   a substantially cylindrical polymeric bullet-end and   a substantially cylindrical polymeric coupling end connected by a powder chamber, wherein the substantially cylindrical polymeric coupling end extends over the substantially cylindrical coupling element and covers an circumferential surface of the primer flash hole.   
     
     
         2 . The polymeric ammunition cartridge of  claim 1 , wherein the substantially cylindrical polymeric middle body is formed from a ductile polymer. 
     
     
         3 . The polymeric ammunition cartridge of  claim 1 , wherein the substantially cylindrical polymeric middle body comprise a nylon polymer. 
     
     
         4 . The polymeric ammunition cartridge of  claim 1 , wherein the substantially cylindrical polymeric middle body is formed from a fiber-reinforced polymeric composite. 
     
     
         5 . The polymeric ammunition cartridge of  claim 4 , wherein the fiber-reinforced polymeric composite contains between about 10 and about 70 wt % glass fiber fillers, mineral fillers, or mixtures thereof. 
     
     
         6 . The polymeric ammunition cartridge of  claim 1 , wherein the substantially cylindrical polymeric bullet-end and bullet are further welded or bonded together. 
     
     
         7 . The polymeric ammunition cartridge of  claim 1 , wherein the substantially cylindrical polymeric bullet-end comprises a forward opening end having a first and a second mechanical interlock for engagement between the forward opening end and a bullet. 
     
     
         8 . The polymeric ammunition cartridge of  claim 1 , wherein the forward opening end comprises one or more cannelures formed on an outer circumferential surface of the forward opening end. 
     
     
         9 . The polymeric ammunition cartridge of  claim 1 , wherein the forward opening end comprises one, two, three, or more annular rings that mate with one, two, three, or more corresponding annular grooves positioned on the bullet. 
     
     
         10 . The polymeric ammunition cartridge of  claim 1 , wherein the forward opening end is crimped so that a polymeric material flows into an annular groove of a bullet. 
     
     
         11 . The polymeric ammunition cartridge of  claim 1 , wherein a bullet is adhesively fitted to the forward opening end. 
     
     
         12 . The polymeric ammunition cartridge of  claim 1 , wherein the substantially cylindrical polymeric middle body comprise a polymers selected from the group consisting of polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of poly-phenylsulfones with siloxanes, blends of polyphenylsulfones with polysiloxanes, poly(etherimide-siloxane) copolymers, blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly(etherimide-siloxane) copolymers. 
     
     
         13 . The polymeric ammunition cartridge of  claim 1 , wherein the forward opening end comprises a neck with a plurality of internal structures for supporting a bullet. 
     
     
         14 . The polymeric ammunition cartridge of  claim 1 , wherein the substantially cylindrical coupling element is a male coupling element with a straight skirt interlock surface that tapers to a smaller diameter at the forward portion on the skirt tip to mate with a female coupling element of the substantially cylindrical polymeric coupling end. 
     
     
         15 . The polymeric ammunition cartridge of  claim 1 , further comprising a diffuser positioned in the primer recess comprising a diffuser flash hole aligned with the primer flash hole.