Abstract: A tool for extending the barrel of a revolver crane and for checking the alignment of the crane barrel and cylinder locking aperture in a revolver frame. The crane barrel is inserted over an alignment stud and an adjustable stylus is threaded into contact with the crane barrel near its end. Rotation of the crane barrel causes a groove to be worn on the outer surface of the crane barrel and thus cause the barrel to elongate to its desired length. Additionally, the alignment stud may be used to align the crane barrel to the revolver cylinder locking aperture.

Abstract: A sight base bridge for an automatic pistol having relative movement between its slide and barrel, said bridge permitting the mounting of sights directly to the pistol barrel, thus eliminating inaccuracy caused by tolerances between the barrel and slide formerly having the sights thereon. A similar mounting system can be used for attachment of silencers and compensators.

Abstract: A spring steel snap ring bearing between the gun barrel and the barrel bushing to remove the relative play therebetween and thus accurately position the barrel relative to the sights on the slide to improve its aiming characteristics. This relative play between the barrel and barrel bushing on the slide is incorporated in its manufacture to permit pivotal as well as longitudinal movement of the barrel relative to the slide containing the bushing.