The Universal Aluminum Bore Guide properly aligns your cleaning rod and protects the chamber, breech and bore from potential abrasive damage caused by the bowing or bending of your cleaning rod.Features : Made of durable anodized aluminum Includes interchangeable tips that fit bore sizes from .17 up to .416 built-in port for mess-free solvent application to the inserted cleaning patch The threaded brass pin anchors the guide rod to the action to prevent it from moving while pushing a cleaning rod through