The Stopper Adjustable Bore Guide 303 to 375 Cal Long & Short Actions Aluminum with Delrin Tip New BG3 Bore Guide slides in place of the bolt carrier group assembly while cleaning. This centers the cleaning rod while the o-ring end prevents solvent from entering the upper receiver and trigger mechanism during the cleaning process. This bore guide can be used for all family of rfls. Pro-Shot’s bore guides are manufactured with precision quality Delrin and include a solvent port. The bore guide is chemical resistant and will stand up to harsh chemicals, providing continual use. ~~~~~~~~~~~~~~~~~~~~~~~~~~~ We are a factory direct dealer of Pro-Shot Products parts and accessories. All of our products are BRAND NEW and contain all of the parts, materials and documentation. You can expect and will receive prompt delivery of your item . We will ship your order within one day . We are unable to accept returns on used, fitted, or altered parts. Returns must be in new, unused condition and in their original packaging.