Bolt Action Centerfire Bore GuideBore Techs CENTERFIRE, BOLT ACTION BORE GUIDES precisely align cleaning rods with the rifle bore and prevent damage to both the firearm and cleaning rod, making it a necessary tool for proper cleaning and protection of your rifles. Color-coded for easy caliber identification, Bore Techs rifle bore guide fits most popular centerfire, Remington 700 style, bolt action rifles ranging from .17 to .416 calibers. Each Bore Tech rifle cleaning bore guide features high-precision CNC machined and injection molded components providing a lifetime of use. The color-coded solvent ports feature widened openings for easy solvent application and a tapered rear access for easy jag/brush alignment. Additionally, the replaceable and solvent-resistant molded rubber nosecones are soft enough to provide a superior, long-lasting seal and completely prevent cleaners from leaking into the chamber and action areas. Designed to fit both short and long actions, these bore guides feature an adjustable bolt collar that firmly locks in place via the threaded locking handle. Description:Green - 8mm - .416 CalCenterfire Bore Guide Length: 13.5 InchesThe included bolt collar will fit most popular centerfire actions with a 0.695 -0.700 bolt diameter. Most Remington, Winchester, Ruger, Browning, and Savage rifles have 0.695 -0.700 bolt diameters.For actions with smaller or larger bolt diameters such as Weatherby, Sako, Kimber, CZ, etc., please have bolt diameter to the nearest 0.001