Disclosed is an autoloading shotgun firearm which shares interchangeable fully compatible modular sub-assemblies, ergonomics, parts commonality, and exterior appearance with the AR rifle platform. Rapidly reversible tool less conversion from rifle to shotgun and vice versa is accomplished by substitution of the AR rifle upper receiver and ammunition detachable magazine with fully compatible shotgun upper receiver and ammunition detachable magazine. Said shotgun utilizes standard rimmed shotgun ammunition via features in the detachable magazine which securely maintain the position and facilitate the feeding of the cartridges during normal operation. No alteration of the AR rifle lower receiver is required. A short-recoil action is integrated into the shotgun upper receiver. The external appearance and functionality of the AR rifle are retained while eliminating the complexity and inherent fouling issues of typical gas systems used in the AR rifle. A short-recoil action also enables the shotgun to function reliably with shorter length barrels.

A bedding block for mounting a barreled action for a rifle to a stock can include an elongated body configured to receive the barreled action for the rifle in a semicircular channel defined in top surface of the elongated body. The semicircular channel can have a first radius, the barreled action can have a second radius, and the first radius can be less than the second radius.

An interchangeable barrel assembly for a firearm including a novel barrel and tool assembly which are used with a receiver having an open aft end. The tool assembly is configured to be inserted into the receiver open aft end so as to engage the aft end of the barrel. Torque applied to the tool assembly thereby transfers torque to the barrel without transferring forces to the action. This enables the same action to be used with different barrels and the barrel may be removed without removing the receiver or other components of the modular chassis or accessories mounted thereon. Additionally, standard torque may be applied to the barrel for connection to the receiver and firearm precision is maintained.

A barrel mounting system to mount a barrel to a barrel mount of a firearm body includes a mount receiver secured to the barrel mount. The mount receiver includes axial channels and receiver threads disposed on an interior surface. The system further includes a barrel sleeve disposed around the barrel proximal to the proximal end of the barrel. The barrel sleeve includes sleeve threads disposed near a proximal end on an exterior surface and sized to slide through the axial channels and, when rotated, to engage the receiver threads. The system further includes a barrel collar disposed around the barrel and secured to the barrel and to limit the axial position of the barrel sleeve.

There is a multi-caliber weapon system. The multi-caliber weapon system comprises: a frame body, with a front body portion, a middle body portion, and a rear body portion, and including: a plurality of frame flanges, each frame flange being coupled to an interior of the frame body and extending upwardly therefrom; a barrel, removably coupled to the front body portion of the frame body, including: a plurality of barrel rings, each barrel ring being disposed around a circumference of the barrel and spaced along a length of the barrel, wherein the barrel rings are disposed on the frame flanges; a chamber, removably coupled to the middle body portion of the frame body, and removably coupled to the barrel; and a bolt, removably coupled to rear body portion of the frame body, removably coupled to the chamber, and including: a bolt face, removably coupled to a front bolt portion.

Disclosed is an autoloading shotgun firearm which shares interchangeable fully compatible modular sub-assemblies, ergonomics, parts commonality, and exterior appearance with the AR rifle platform. Rapidly reversible tool less conversion from rifle to shotgun and vice versa is accomplished by substitution of the AR rifle upper receiver and ammunition detachable magazine with fully compatible shotgun upper receiver and ammunition detachable magazine. Said shotgun utilizes standard rimmed shotgun ammunition via features in the detachable magazine which securely maintain the position and facilitate the feeding of the cartridges during normal operation. No alteration of the AR rifle lower receiver is required. A short-recoil action is integrated into the shotgun upper receiver. The external appearance and functionality of the AR rifle are retained while eliminating the complexity and inherent fouling issues of typical gas systems used in the AR rifle. A short-recoil action also enables the shotgun to function reliably with shorter length barrels.

An interchangeable barrel assembly for a firearm including a novel barrel and tool assembly which are used with a receiver having an open aft end. The tool assembly is configured to be inserted into the receiver open aft end so as to engage the aft end of the barrel. Torque applied to the tool assembly thereby transfers torque to the barrel without transferring forces to the action. This enables the same action to be used with different barrels and the barrel may be removed without removing the receiver or other components of the modular chassis or accessories mounted thereon. Additionally, standard torque may be applied to the barrel for connection to the receiver and firearm precision is maintained.

A bedding block for mounting a barreled action for a rifle to a stock can include an elongated body configured to receive the barreled action for the rifle in a semicircular channel defined in top surface of the elongated body. The semicircular channel can have a first radius, the barreled action can have a second radius, and the first radius can be less than the second radius.

Disclosed is an autoloading shotgun firearm which shares interchangeable fully compatible modular sub-assemblies, ergonomics, parts commonality, and exterior appearance with the AR rifle platform. Rapidly reversible tool less conversion from rifle to shotgun and vice versa is accomplished by substitution of the AR rifle upper receiver and ammunition detachable magazine with fully compatible shotgun upper receiver and ammunition detachable magazine. Said shotgun utilizes standard rimmed shotgun ammunition via features in the detachable magazine which securely maintain the position and facilitate the feeding of the cartridges during normal operation. No alteration of the AR rifle lower receiver is required. A short-recoil action is integrated into the shotgun upper receiver. The external appearance and functionality of the AR rifle are retained while eliminating the complexity and inherent fouling issues of typical gas systems used in the AR rifle. A short-recoil action also enables the shotgun to function reliably with shorter length barrels.

Disclosed is an autoloading shotgun firearm which shares interchangeable fully compatible modular sub-assemblies, ergonomics, parts commonality, and exterior appearance with the AR rifle platform. Rapidly reversible tool less conversion from rifle to shotgun and vice versa is accomplished by substitution of the AR rifle upper receiver and ammunition detachable magazine with fully compatible shotgun upper receiver and ammunition detachable magazine. Said shotgun utilizes standard rimmed shotgun ammunition via features in the detachable magazine which securely maintain the position and facilitate the feeding of the cartridges during normal operation. No alteration of the AR rifle lower receiver is required. A short-recoil action is integrated into the shotgun upper receiver. The external appearance and functionality of the AR rifle are retained while eliminating the complexity and inherent fouling issues of typical gas systems used in the AR rifle. A short-recoil action also enables the shotgun to function reliably with shorter length barrels.