A caseless ammunition cartridge includes a unitary outer portion having forward, central section and rear sections. The forward section has an aerodynamic tangent ogive profile. The rear section has a cylindrical profile. The central section has a conical profile that transitions from the radius of the forward section to the radius of the rear section. An inner core, disposed within the unitary metallic outer portion, has a front portion encased by the forward section of the unitary outer portion, and a cylindrical rear portion disposed within the central and rear sections of the unitary outer portion. An annular cavity is disposed between the unitary outer portion and the rear portion of the inner core. A propellant is disposed within the annular cavity. A combustible seal covers the annular cavity to protect the propellant.

A low energy cartridge has a case having a sidewall with an interior surface defining a projectile receptacle along a bore axis and having a forward open case mouth, a projectile having an exterior sidewall closely received in the projectile receptacle and defining a rotational axis, a propellant receptacle defined by the case and having a passage communicating with the projectile receptacle, the projectile exterior sidewall being non-circular in cross section across the rotational axis, and the case sidewall interior surface having a rotational engagement feature configured to rotationally engage the non-circular projectile exterior sidewall. The projectile may be slidably received in the projectile receptacle for propulsion from the forward open case mouth. At least one of the projectile and the sidewall interior surface may have a helical surface feature, such that spin is imparted to the projectile upon propulsion from the case.

The disclosure generally relates to systems, devices, and methods for sound suppression for firearms. In various embodiments, the firearm suppressor can include a barrel system of a predetermined length to prevent supersonic projectile (e.g., bullet) speed. Further, the firearm suppressor can include a plurality of chambers that can substantially contain the gases released from a projectile and thereby reduce the sound generated by the expansion of the gases release upon firing the projectile.

The disclosure generally relates to systems, devices, and methods for sound suppression for firearms. In various embodiments, the firearm suppressor can include a barrel system of a predetermined length to prevent supersonic projectile (e.g., bullet) speed. Further, the firearm suppressor can include a plurality of chambers that can substantially contain the gases released from a projectile and thereby reduce the sound generated by the expansion of the gases release upon firing the projectile.

A barrel for use in a firearm optimized to fire subsonic ammunition with high precision. The barrel groove diameter being within .0003 inch of the nominal bullet diameter and the barrel has at least 8 rifled grooves. Each of the plurality of rifling grooves has a sidewall formed from the bore diameter to the groove diameter, wherein the sidewalls formed are substantially parallel and the depth of each of the rifling grooves is shallow. The bullet is obturated as the bullet is forced down the bore. The plurality of shallow barrel grooves forming a plurality of raised lands upon the bullet. The obturated bullet having at least 50% lands formed around the circumference of the bullet body. The buffeting effect upon the bullet in flight by a transition shock wave upon the raised bullet lands is reduced by the plurality of bullet lands and the reduced height of each of the plurality of bullet lands.

A barrel for use in a firearm optimized to fire subsonic ammunition with high precision. The barrel groove diameter being within .0003 inch of the nominal bullet diameter and the barrel has at least 8 rifled grooves. Each of the plurality of rifling grooves has a sidewall formed from the bore diameter to the groove diameter, wherein the sidewalls formed are substantially parallel and the depth of each of the rifling grooves is shallow. The bullet is obturated as the bullet is forced down the bore. The plurality of shallow barrel grooves forming a plurality of raised lands upon the bullet. The obturated bullet having at least 50% lands formed around the circumference of the bullet body. The buffeting effect upon the bullet in flight by a transition shock wave upon the raised bullet lands is reduced by the plurality of bullet lands and the reduced height of each of the plurality of bullet lands.

Air guns and non-firearm guns for conventional metal jacket bullets are provided. Novel chamber and throat geometries, novel barrel rifling schemes, barrel materials, and surface technology facilitate manufacture or retrofit of air guns and other non-firearm guns to use standard size metal jacket bullets manufactured for conventional firearms.

Air guns and non-firearm guns for conventional metal jacket bullets are provided. Novel chamber and throat geometries, novel barrel rifling schemes, barrel materials, and surface technology facilitate manufacture or retrofit of air guns and other non-firearm guns to use standard size metal jacket bullets manufactured for conventional firearms.

An barrel (or barrel section) for a pneumatic gun can comprise a plurality of grooves and ridges arranged in parallel straight lines. The ridges may have a substantially arch-shaped cross-section with a rounded upper surface to provide minimal contact with a projectile such as a paintball being launched through the barrel. The grooves preferably provide channels to permit water and debris to be expelled from the barrel without interfering with the projectile travel. A plurality of apertures may be formed through a sidewall of the barrel along one or more of the grooves to further help expel water and debris, to impart spin to the projectile, and/or to improve a sound signature of the barrel.

An barrel (or barrel section) for a pneumatic gun can comprise a plurality of grooves and ridges arranged in parallel straight lines. The ridges may have a substantially arch-shaped cross-section with a rounded upper surface to provide minimal contact with a projectile such as a paintball being launched through the barrel. The grooves preferably provide channels to permit water and debris to be expelled from the barrel without interfering with the projectile travel. A plurality of apertures may be formed through a sidewall of the barrel along one or more of the grooves to further help expel water and debris, to impart spin to the projectile, and/or to improve a sound signature of the barrel.