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 propellent 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 propellent 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.

An explosive composition for use in telescopically expanding non-lethal training ammunition comprises tetrazene and paraffin wax. The explosive composition can be used as a primer and/or as a source of energetic material in a telescopically expanding non-lethal training cartridge; it can be used to propel a projectile from a telescopically expanding non-lethal training cartridge; and/or it can be used to expand telescopically a non-lethal training cartridge within a host gun.

An explosive composition for use in telescopically expanding non-lethal training ammunition comprises tetrazene and paraffin wax. The explosive composition can be used as a primer and/or as a source of energetic material in a telescopically expanding non-lethal training cartridge; it can be used to propel a projectile from a telescopically expanding non-lethal training cartridge; and/or it can be used to expand telescopically a non-lethal training cartridge within a host gun.

A system, device, and method for measuring the temperature of a chambered projectile within a firearm are provided. A test ammunition round may include a projectile, a sleeve, and a case including a first end coupled to sleeve, and a second end coupled to the projectile. A thermocouple may be located within the projectile, and an electronic coupler may be coupled to the thermocouple, and extends through the case and the sleeve and exits the sleeve through a slot for coupling to a data acquisition system.

A system, device, and method for measuring the temperature of a chambered projectile within a firearm are provided. A test ammunition round may include a projectile, a sleeve, and a case including a first end coupled to sleeve, and a second end coupled to the projectile. A thermocouple may be located within the projectile, and an electronic coupler may be coupled to the thermocouple, and extends through the case and the sleeve and exits the sleeve through a slot for coupling to a data acquisition system.

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. The power load seats in in the casing surrounded by a reinforcement liner embedded in the polymer casing.

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. The power load seats in in the casing surrounded by a reinforcement liner embedded in the polymer casing.

A magazine for projectiles in a simulated weapon includes a housing defining an internal chamber. A gas inlet is situated at an inlet portion of the internal chamber. An outlet situated at an outlet portion of the internal chamber. The internal chamber of the housing is shaped to accommodate a series of spherical projectiles. A restraining element is positioned at the outlet portion of the internal chamber. The restraining element restrains a lead projectile of the series of projectiles against pressure from pressurized gas applied to the gas inlet. The restraining element releases the lead projectile as pressure within the internal chamber rises. The magazine can be integrated in a simulated grenade, simulated shotgun shell, and similar devices.