Bore Guides should be usedwhen cleaning a Bolt Action Rifle. Bore Guides protect the bore throat and keep cleaning solvent from getting into the trigger mechanism. Our Bore Guides are made from aircraft grade anodized aluminum, even the sleeve. The Stopper bore guides are mfg.with delrin tips and ends. The sleeve pin is made of brass. All other Pro-Shot bore guides are mfg. using delrin. Delrin is a chemical resistant material that will stand up to continual use. Available in the actions listed in the charts.