A compact survival firearm is a rifle having an upper receiver body, a lower receiver body removably connectable to the upper receiver body and defining a transverse bore adapted to closely receive a takedown pin, a fastener connected to the upper receiver body and having a protruding portion protruding therefrom, the lower receiver body defining a space sized to closely receive the fastener, the protruding portion of the fastener having an end portion of a first width, and an intermediate portion of a second width less than the first width, and the space at least partially intersecting the transverse bore such that the intermediate portion of the fastener is clear of the bore to permit the presence of the takedown pin, and the end portion of the fastener prevents separation of the upper receiver from the lower receiver when a takedown pin is present in the bore.

A compact survival firearm is a rifle having an upper receiver body, a lower receiver body removably connectable to the upper receiver body and defining a transverse bore adapted to closely receive a takedown pin, a fastener connected to the upper receiver body and having a protruding portion protruding therefrom, the lower receiver body defining a space sized to closely receive the fastener, the protruding portion of the fastener having an end portion of a first width, and an intermediate portion of a second width less than the first width, and the space at least partially intersecting the transverse bore such that the intermediate portion of the fastener is clear of the bore to permit the presence of the takedown pin, and the end portion of the fastener prevents separation of the upper receiver from the lower receiver when a takedown pin is present in the bore.

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.

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.

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.

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.

An assembly of a receiver (1) with a barrel (4) wherein the barrel (4) is inserted into a barrel hole (7) in the receiver (1) and is attached in a replaceable manner by means of a clamping connection that comprises a longitudinal slot (2) that longitudinally divides the receiver (1) wall in the insertion location of the barrel (4). In the location of the longitudinal slot (2) at least two transversal screws (3) pass through the receiver (1). In the location of the longitudinal slot (2), a transversal hole (5) extends into the receiver (1) and a transversal pin (10) passes through the transversal hole (5) in such a way that the transversal pin (10) reaches into a corresponding transversal recess (9) in the barrel (4). Perpendicularly to the longitudinal axis of the transversal pin (10) a threaded hole (11) with a connecting screw (12) passes through the transversal pin (10). The connecting screw (12) further passes through a straight-through hole (6) in the receiver (1) and through a stock/frame (13) of the firearm to connect the receiver (1) to the stock/frame (13) of the firearm.

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.

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.

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.