Patent attributes
An auxiliary caliber weapon system that allows a conventional shotgun, such as a pump action shotgun or other firearm, including artillery weapons to be modified to fire ammunition rounds of a selectable caliber. The system includes a barrel assembly and to load an ammunition round within the shotgun or other firearm and a shotgun shell adapter of a selected auxiliary caliber is utilized. The shotgun includes a stock with grip a receiver and an internal magazine. The shotgun barrel is removed and the system's barrel assembly is attached to the shotgun, interfacing with the receiver. An ammunition round of a selected auxiliary caliber is inserted into the adapter, which is then placed into the magazine via a loading port. When the shotgun pump is actuated the adapter with the auxiliary caliber round is loaded from the magazine into the receiver, and is ready to be fired. After being fired, the pump is actuated again causing the adapter to be ejected out an ejection port and another adapter with an auxiliary caliber round to be loaded. For use with an artillery weapon, the adapter is scaled to a larger dimension to accommodate the larger size ammunition used but the functionality is the same.