A bolt action firearm that cocks the firing pin upon closing the bolt and includes a cam pin for a high velocity rimfire cartridge. In one embodiment, actuating the main spring while closing the bolt, instead of while opening the bolt, provides added safety against misfiring. A safety system is provided for the trigger mechanism and a robust connecting system for the stock.

A firearm handguard assembly system is disclosed. The system comprises a handguard including at least four apertures, a barrel nut having a first threaded end and a second smooth end, the threaded end coupled to the handguard, and an index block including at least four apertures, the index block coupled to the handguard by at least four screws, each screw having a head and a tip, the tip threaded through: one of the at least four apertures on the index block, and one of the at least four apertures on the handguard.

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 gun body includes a gun body side connection portion, a barrel includes a barrel side connection portion, and the gun body side connection portion and the barrel side connection portion are connected to each other by an insertion structure. The gun body side connection portion includes an inner peripheral surface which is formed inward from a connection opening, the barrel side connection portion includes an outer peripheral surface, at least one of the inner peripheral surface and the outer peripheral surface is formed in a tapered shape, and the other of the inner peripheral surface and the outer peripheral surface is formed in a shape which is movable along the tapered shape. The gun body side connection portion and the barrel side connection portion are drawn in a direction along a center line by coupling means, the inner peripheral surface or the outer peripheral surface having the tapered shape and the movable shape are fitted to each other, and the barrel is centered.

A slide for a rifle with a slide operating mechanism, which is movable in the longitudinal direction of the rifle, and a slide element, which can be moved by the slide operating mechanism between a locked position and an unlocked position. The slide operating mechanism is connected to the slide element via a control element, which is movable transversely to the slide element and is designed as a connector that cooperates with the slide element for its displacement between the upper, locked position and the lower, unlocked position.

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 firearm handguard assembly system is disclosed. The system comprises a handguard including at least four apertures, a barrel nut having a first threaded end and a second smooth end, the threaded end coupled to the handguard, and an index block including at least four apertures, the index block coupled to the handguard by at least four screws, each screw having a head and a tip, the tip threaded through: one of the at least four apertures on the index block, and one of the at least four apertures on the handguard.

A bolt action firearm that cocks the firing pin upon closing the bolt and includes a cam pin for a high velocity rimfire cartridge. In one embodiment, actuating the main spring while closing the bolt, instead of while opening the bolt, provides added safety against misfiring. A safety system is provided for the trigger mechanism and a robust connecting system for the stock.

An apparatus includes a barrel nut having an inner portion and an outer portion. The inner portion includes a threaded portion and a shoulder. The shoulder is configured to engage a shoulder of a barrel to retain the barrel within a receiver when the threaded portion is coupled to a corresponding threaded portion of the receiver. The outer portion defines an outer diameter such that a gas port of the receiver is exposed independent of a rotational position of the barrel nut relative to the receiver. The outer portion includes an engagement surface and a lock surface. The engagement surface is configured to engage a mounting surface of a handguard. The lock surface defines a frusto-conical shape configured to contact a set screw threadedly engaged with the handguard such that rotational movement of the set screw moves the handguard axially relative to the barrel nut.

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.