Stoppage-inducing ammunition cartridges have a case having a rear head surface, a circumferential extractor groove forward of the rear head surface, a body portion forward of the circumferential extractor groove defining a case axis perpendicular to the rear head surface, and a forward mouth, a primer received in the case, a propellant within the case, a bullet received in the forward mouth, and the circumferential extractor groove being defined in part by a rear extractor surface angularly disposed with respect to a plane perpendicular to the case axis, such that an extractor adapted to engage a groove surface perpendicular to the case axis will have limited effect at extracting the cartridge from a firearm chamber after discharge. The rear extractor surface may be a frustoconical surface. The rear extractor surface may be a tapered surface acutely angled with respect to the case axis.

Stoppage-inducing ammunition cartridges have a case having a rear head surface, a circumferential extractor groove forward of the rear head surface, a body portion forward of the circumferential extractor groove defining a case axis perpendicular to the rear head surface, and a forward mouth, a primer received in the case, a propellant within the case, a bullet received in the forward mouth, and the circumferential extractor groove being defined in part by a rear extractor surface angularly disposed with respect to a plane perpendicular to the case axis, such that an extractor adapted to engage a groove surface perpendicular to the case axis will have limited effect at extracting the cartridge from a firearm chamber after discharge. The rear extractor surface may be a frustoconical surface. The rear extractor surface may be a tapered surface acutely angled with respect to the case axis.

A method and tooling for forming a cartridge case blank comprising backward extruding a tube from a length of wire stock in multiple backward extrusion steps with progressive tooling to obtain an intermediate blank that can be finish drawn without a preceding annealing step and which if otherwise not subjected to multiple backward extrusion steps, would require annealing prior to finish drawing to avoid tearing.

A method and tooling for forming a cartridge case blank comprising backward extruding a tube from a length of wire stock in multiple backward extrusion steps with progressive tooling to obtain an intermediate blank that can be finish drawn without a preceding annealing step and which if otherwise not subjected to multiple backward extrusion steps, would require annealing prior to finish drawing to avoid tearing.

In various embodiments, a projectile includes a projectile body including a tail portion, a nose portion, a barrel engaging portion between the nose portion and the tail portion, and a metal jacket that defines an exterior of the projectile that surrounds an interior solid core. In one or more embodiments the projectile includes one or more circumferential grooves defined in the interior core portion, each of the one or more circumferential grooves covered by and positioned adjacent to the metal jacket and within the barrel-engaging portion. In various embodiments, during firing of the projectile, the one or more circumferential grooves define a void that allows material of one or more of the metal jacket and interior solid core to displace into the void for reduction in radial stiffness to the projectile in the barrel engaging portion.

In various embodiments, a projectile includes a projectile body including a tail portion, a nose portion, a barrel engaging portion between the nose portion and the tail portion, and a metal jacket that defines an exterior of the projectile that surrounds an interior solid core. In one or more embodiments the projectile includes one or more circumferential grooves defined in the interior core portion, each of the one or more circumferential grooves covered by and positioned adjacent to the metal jacket and within the barrel-engaging portion. In various embodiments, during firing of the projectile, the one or more circumferential grooves define a void that allows material of one or more of the metal jacket and interior solid core to displace into the void for reduction in radial stiffness to the projectile in the barrel engaging portion.

The present invention provides steel compositions, methods of manufacturing the compositions and using the compositions to produce rimfire ammunition cartridges. The steel compositions are substitutes for conventional brass used in the manufacture of rimfire ammunition cartridges and, in particular, for use in .22 caliber firing devices. Also provided are methods of processing and treating the steel compositions for use in the rimfire cartridges that include cold-rolling and annealing steps to create suitable physical properties.

The present invention provides steel compositions, methods of manufacturing the compositions and using the compositions to produce rimfire ammunition cartridges. The steel compositions are substitutes for conventional brass used in the manufacture of rimfire ammunition cartridges and, in particular, for use in .22 caliber firing devices. Also provided are methods of processing and treating the steel compositions for use in the rimfire cartridges that include cold-rolling and annealing steps to create suitable physical properties.

A boron steel high pressure cartridge case and method of manufacturing the same is provided. The method includes cold forming a cartridge case into a drawn blank or a tubular component; annealing the cartridge case using a belt furnace, flame furnace, induction furnace, or a batch furnace; performing a machine ejector slot and trim on the cartridge case; forming the shoulder and neck of the cartridge case; performing a heat treatment of the cartridge case; tempering the cartridge case; and coating the cartridge case with a zinc nickel plating. The cartridge case is fabricated of boron steel including 1.0% boron.

A boron steel high pressure cartridge case and method of manufacturing the same is provided. The method includes cold forming a cartridge case into a drawn blank or a tubular component; annealing the cartridge case using a belt furnace, flame furnace, induction furnace, or a batch furnace; performing a machine ejector slot and trim on the cartridge case; forming the shoulder and neck of the cartridge case; performing a heat treatment of the cartridge case; tempering the cartridge case; and coating the cartridge case with a zinc nickel plating. The cartridge case is fabricated of boron steel including 1.0% boron.