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 device and method for producing a secondary malfunction of a cartridge extracted from a firearm. A cartridge case has a bullet disposed in a front end and a rim formed at a rear end. The rim is tapered toward a primer, wherein the primer is disposed in the center of the rim. The tapered rim prevents a firearm from successfully extracting the cartridge case, i.e. a secondary malfunction occurs.

A device and method for producing a secondary malfunction of a cartridge extracted from a firearm. A cartridge case has a bullet disposed in a front end and a rim formed at a rear end. The rim is tapered toward a primer, wherein the primer is disposed in the center of the rim. The tapered rim prevents a firearm from successfully extracting the cartridge case, i.e. a secondary malfunction occurs.

Systems, methods and apparatus are provided through which in some implementations an ammunition cartridge includes a cartridge casing having a longitudinal center axis, a powder pocket positioned adjacent to the cartridge casing, a piston bore positioned adjacent to the powder pocket, a piston in the piston bore, and a payload bay positioned adjacent to the payload bay, wherein the piston is not coupled to the cartridge, wherein the piston is in direct contact with the payload bay wherein a diameter of the powder pocket is less than an inside diameter of the cartridge casing to provide a reduced velocity to the payload.

Systems, methods and apparatus are provided through which in some implementations an ammunition cartridge includes a cartridge casing having a longitudinal center axis, a powder pocket positioned adjacent to the cartridge casing, a piston bore positioned adjacent to the powder pocket, a piston in the piston bore, and a payload bay positioned adjacent to the payload bay, wherein the piston is not coupled to the cartridge, wherein the piston is in direct contact with the payload bay wherein a diameter of the powder pocket is less than an inside diameter of the cartridge casing to provide a reduced velocity to the payload.

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 system for firing reduced energy cartridges from a modern sporting rifle utilizes a bolt assembly weighing less than a conventional bolt assembly for such rifles and utilizes blow back for cycling the bolt assembly rather than gas operation. A bolt insert in a polymer bolt carrier of the bolt assembly has a projection that fits within a recess on the rear face of reduced energy cartridges. The reduced energy cartridges having a polymer casing, a rimfire power load for propellant, the power load recessed from the rear face of the casing. Tuning the bolt may comprise adjusting the weight of the bolt or the sliding resistance of the bolt assembly in the upper receiver. The bolt may be formed by metal injection molding with a polymer bolt carrier attached thereto.

Training ammunition that may be utilized by the U.S. Army, Marines and other Armed Forces that conduct training exercises with about 20 mm to 155 mm cartridges. The munition would electronically generate/initiated a signature that would become present at the target. The user would be able to observe the signature with the unaided eye during day or night training, or with devices such as night vision goggles/monocular or thermal sites. The generated signature would not utilize any explosives or pyrophoric iron powders, and would not create an increased fire hazard risk to the user. The munition would be able to survive typical rough handling and firing weapon malfunctions without becoming unusable, or causing delays in training exercises.

Training ammunition that may be utilized by the U.S. Army, Marines and other Armed Forces that conduct training exercises with about 20 mm to 155 mm cartridges. The munition would electronically generate/initiated a signature that would become present at the target. The user would be able to observe the signature with the unaided eye during day or night training, or with devices such as night vision goggles/monocular or thermal sites. The generated signature would not utilize any explosives or pyrophoric iron powders, and would not create an increased fire hazard risk to the user. The munition would be able to survive typical rough handling and firing weapon malfunctions without becoming unusable, or causing delays in training exercises.