The bore tech bore guide features CNC machined and anodized aluminum tubes, bolt collars, and patch pates to provide long lasting Quality.The molded rubber nose cones allow for a superior fit and prevent solvents from leaking back into the chamber and action. The solvent port has a tapered opening for easy jag/brush alignment. An adjustable bolt collar is firmly locked in place by a threaded brass handle.The bolt collars included with each bore guide will fit most standard centerfire actions with a 0.695 to 0.700 bolt diameter including remington, winchester, ruger, browning, savage, mauser etc.For actions such as weatherby,sako, kimber, cz etc.,please have bolt diameter to nearest .001.Specifications:- Caliber: .17-.25- Bore tech guide will add approximately 14 inches to the length of the barrel when cleaning. - Make sure cleaning rod is long enough to accommodate