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. The Universal Aluminum Bore Guide kit will fit most bolt-action rifles and includes an adapter sleeve for the AR15, which creates a tighter fit and provides additional support to the upper receiver while cleaning your rifle. Made of durable anodized aluminum and includes interchangeable tips that fit bore sizes from .17 up to .416 which allow the guide to smoothly move through the chamber. Includes a 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.