Abstract: An assembly is described for use in attaching accessories to a firearm having a barrel with a threaded distal end. The assembly includes a coupler with opposed, inwardly curved side plates that together form a cylindrical bore for receiving the firearm barrel attachable behind the threaded distal end, the side plates have integrally joined upper ends and lower ends that are moveable toward each other to clamp the coupler to the barrel, the coupler including a retractable pin having an extended position and a retracted position; and an adapter having a rear end with a threaded bore for receiving the barrel threaded end, and a front end with a threaded projection for attachment to a firearm accessory, the adapter including a groove to receive the retractable pin when the retractable pin is in the extended position.

Abstract: An assembly is described for use in attaching accessories to a firearm having a barrel with a threaded distal end. The assembly includes a coupler with opposed, inwardly curved side plates that together form a cylindrical bore for receiving the firearm barrel attachable behind the threaded distal end, the side plates have integrally joined upper ends and lower ends that are moveable toward each other to clamp the coupler to the barrel, the coupler including a retractable pin having an extended position and a retracted position; and an adapter having a rear end with a threaded bore for receiving the barrel threaded end, and a front end with a threaded projection for attachment to a firearm accessory, the adapter including a groove to receive the retractable pin when the retractable pin is in the extended position.