A grenade launcher may include at least one barrel for receiving a grenade, a support for releasably mounting the grenade launcher to a carrier, and a receiving slot receiving a removable primer cartridge. The primer cartridge when received in the receiving slot may hold a primer in position for firing the grenade in the barrel.

A rifle comprises a quad lock multicaliber receiver, a barrel extension, a bolt, and a projection engageable with the receiver. The barrel extension includes a cartridge chamber and is securable in an end of the receiver. The bolt is slideable in the receiver and engages a cartridge in the cartridge chamber during the firing phase. The projection comprises locking bars extending through the receiver, and is moveable between locked and unlocked positions to allow for securing and removing of the barrel extension, respectively. Positioning bars are disposed on either side of the receiver split parallel to its longitudinal axis. The locking bars are disposed between these positioning bars and the barrel extension such that when the positioning bars are urged toward each other the receiver split is closed and the positioning bars urge the locking bars toward and into locking grooves to secure the barrel extension in the receiver.

A pistol having a handle piece, a slide that is movable on the handle piece along guides, and a barrel. Provided in the handle piece is a blocking device for the forward movement of the barrel, where the blocking device has a retaining platelet that is movable in a slot and is under the action of a spring, for a barrel projection. A spring platelet is provided in the slot between the spring and the retaining platelet, where the spring platelet is designed such that it can be partially extracted from the slot transversely with respect to the center plane of the pistol. In this extracted position, the spring platelet is pivotable, together with the retaining platelet, against the force of the spring, with the result that the retaining platelet passes out of the movement path of the barrel projection and the slide can be withdrawn forward.

Quick take-down firearms and methods of using quick-take down firearms. The quick-take down includes an upper receiver coupling and a barrel coupling. The quick take-down can be unlocked by sliding a sliding lock collar in a translational motion to an unlocked position to release locking elements from a locked configuration. In the unlocked position, a barrel and handguard may be installed onto and removed from the upper receiver of the firearm. Releasing the sliding lock collar returns it to a locked position, securing the barrel and handguard to the upper receiver.

A take-down rifle is provided which may be broken down for transport, reassembled, and employed to engage a target up to 500 meters away without the need to re-zero rifle before engagement.

A system for securing a barrel to a receiver of a rifle is provided, the barrel having a barrel axis, a muzzle end and a receiver end, the system comprising a barrel extension having a barrel end and a receiver end, the barrel extension having internal threads at its barrel end for receiving external threads on the barrel, wherein the barrel extension is tapered at the receiver end to mate with a corresponding tapered aperture in the receiver, whereby urging the barrel extension into the receiver, seats and aligns the barrel within the receiver.

A takedown firearm that may utilize removable barrels of different calibers. The disclosed firearm does not require a barrel extension, instead providing positioning of the barrel that is sufficiently precise and repeatable. Tensioning of the barrel is provided passively during installation of the removable barrel, without need for adjustment or additional tightening. Securing the removable barrel to the receiver does not structurally involve the fore end, thereby avoiding harmonics effects associated with fore end interfaces to the receiver. The firearm takes advantage of an underspaced chamber arrangement to provide additional tolerance for manufacturing and assembly of the firearm.

A barrel nut assembly for a firearm is disclosed. The barrel nut assembly may include a barrel nut comprising a plurality of expansion flanges. The barrel nut assembly also may include an expansion plug comprising an expansion surface. The expansion surface may be configured to abut and expand the plurality of expansion flanges when the expansion plug is attached to the barrel nut.

A practice weapon, having a conventional handle piece with a lock for a drop barrel, with a trigger mechanism which optionally has a rotary bearing for a rotatable trigger, with a spring base on which the return spring is supported; and with a practice breech with a fixed practice barrel. In order to permit a conversion without the use of a tool, an adapter is inserted into the handle piece, the adapter being supported firstly above the trigger mechanism, optionally above the rotary bearing, on a brace and secondly in the upper region of the spring base of the handle piece. Furthermore, the upper region of the adapter has guides for the practice barrel, and the lock interacts with a locking carriage, which is formed in a locking slot of the adapter, in such a manner that the locking carriage secures the practice barrel.

A gun device allowing replacement of barrels with different sizes, having a gun body, one end of the gun body has an opening. The opening outer edge has a threading and a positioning slot. The gun body connects with a first size barrel by connecting the threading with a lock. The gun device further comprising: a guide adapter, a second size barrel and a barrel key. The guide adapter has a positioning body, a projecting part, and a first groove, the projecting part alignment connects with the positioning slot. The second size barrel has a second groove, the first groove corresponding with the second groove.