A rotating bolt firearm may be configured to fire a .308 cartridge. However, the firearm may have a reduced weight in comparison to standard .308 rifles. The firearm may have many components typically used in a .223 rifle. The firearm may include a barrel extension with an extractor gap, which allows a .308 bolt to fit within a .223 sized barrel extension. The firearm may comprise an elongated magazine well in comparison to a .223 mil-spec rifle. The firearm may weigh less than 6.8 pounds with a 16 inch barrel, or less than 6.3 pounds with a 10.5 inch barrel.

A rotating bolt firearm may be configured to fire a .308 cartridge. However, the firearm may have a reduced weight in comparison to standard .308 rifles. The firearm may have many components typically used in a .223 rifle. The firearm may include a barrel extension with an extractor gap, which allows a .308 bolt to fit within a .223 sized barrel extension. The firearm may comprise an elongated magazine well in comparison to a .223 mil-spec rifle. The firearm may weigh less than 6.8 pounds with a 16 inch barrel, or less than 6.3 pounds with a 10.5 inch barrel.

A gun barrel unit for a toy gun includes: an inner barrel and an outer barrel, the inner barrel is axially inserted in the outer barrel, at least one rotary member is provided between the inner and outer barrels to allow for rotation of the inner barrel with respect to the outer barrel, and at least one eccentric weight is fixed in the inner barrel. The inner barrel is pivotable and the inner barrel is provided with the eccentric weight, so that even when the gun is held in an inclined position, the inner barrel still can return to a non-inclined manner to ensure the ballistic trajectory stability when firing. Besides, an engaging assembly is provided at the rear end of the inner barrel, so that the inner barrel can still be fixed to the outer barrel in a fixed manner to facilitate ballistic trajectory adjustment.

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.

A disrupter cannon includes a barrel for launching a projectile. An insert may be used to launch a projectile of a smaller diameter than the projectile launched through the barrel of the disrupter cannon. An insert includes a bore therethrough, a breech-end portion, and a muzzle-end portion. The breech-end portion includes a channel. An O-ring is positioned in the channel of the breech-end portion. The muzzle-end portion includes one or more channels. A respective O-ring is positioned in each channel of the muzzle-end portion. While the insert is positioned in the barrel, the O-rings are configured to form a seal between an outer surface of the insert and an inner surface of the barrel. The projectile with a smaller diameter is launched through the bore of the insert.

A disrupter cannon includes a barrel for launching a projectile. An insert may be used to launch a projectile of a smaller diameter than the projectile launched through the barrel of the disrupter cannon. An insert includes a bore therethrough, a breech-end portion, and a muzzle-end portion. The breech-end portion includes a channel. An O-ring is positioned in the channel of the breech-end portion. The muzzle-end portion includes one or more channels. A respective O-ring is positioned in each channel of the muzzle-end portion. While the insert is positioned in the barrel, the O-rings are configured to form a seal between an outer surface of the insert and an inner surface of the barrel. The projectile with a smaller diameter is launched through the bore of the insert.

A firearm for firing case-telescoped (CT) rounds includes a barrel configured for transit of a bullet of a live CT cartridge in a live-fire operating mode. The live CT cartridge is chambered and fired from a live-fire chamber installed in the live-fire operating mode. The firearm further includes a blank-fire chamber configured to chamber and fire a blank CT cartridge in a blank-fire operating mode, wherein the blank-fire chamber has a second diameter less than a first diameter of the live-fire chamber, to prevent chambering of the live CT cartridge in the blank-fire operating mode. The arrangement can enhance safety by preventing accidental firing of a live round during operation when it is assumed that only blanks are being fired.

A firearm for firing case-telescoped (CT) rounds includes a barrel configured for transit of a bullet of a live CT cartridge in a live-fire operating mode. The live CT cartridge is chambered and fired from a live-fire chamber installed in the live-fire operating mode. The firearm further includes a blank-fire chamber configured to chamber and fire a blank CT cartridge in a blank-fire operating mode, wherein the blank-fire chamber has a second diameter less than a first diameter of the live-fire chamber, to prevent chambering of the live CT cartridge in the blank-fire operating mode. The arrangement can enhance safety by preventing accidental firing of a live round during operation when it is assumed that only blanks are being fired.

System for a multi-caliber self-loading action. Specifically, the system is comprised of a multi-position locking assembly and a self-regulating gas assembly. The multi-position locking assembly is comprised of a bolt carrier, a spring, a bolt, a lock, and a cam assembly. The cam assembly will interface between the bolt carrier and the bolt to rotate the bolt through the bolt carrier. The lock will interface with the bolt, to lock the bolt in at least one locked position based on the caliber of the round inserted. The self-regulating gas assembly directs gas from the gas regulation to at least one piston cup, which will then cause the piston to act on the multi-position locking assembly.