Sinclair O-Ring Rod Guide, 308/30-06 Family, Md: Sin003695308 Sinclair's Centerfire Cleaning Rod Guides Are Designed To Insert Into Your Action In Place Of Your Bolt Or Bolt Carrier. They Feature a Snout With a Silicone O-Ring That inserts Into Your Chamber, sealing The Barrel Off From The Receiver. The O-Ring prevents solvents From leaking Back Into The Action Area And Gumming Up The Trigger Assembly. Sinclair Currently Stock O-Ring Rod guides For Over 1000 Different Action/Cartridge combinations. Each Rod Guide Is machined To Fit Specific Actions And Cartridge families From .17 Up To .338 Caliber. Unfortunately Some Rifle chamberings Do Not Lend Themselves To An O-Ring Style Rod Guide, For These Cartridges We recommend One Of Our Adjustable Cone Style Rod Guides. Action Fit: Bordon Rimrock, Brno, Browning A-Bolt, Cooper 22, Cooper 54, Cooper Model 16, Cps, Dakota Arms, Enfield US M1917, Ga Precision Templar, Grunig Elmiger, H-S Precision, Hart Actions, Herter Model V9, Husqvarna Model HVA & M8000, Mauser 3000, Stillar Viper Bolt Diameter: .695 Cartridge: 280 Remington, 280 Remington Imp 40, 280 Remington Ackley Improved, 7 mm - 08 Remington, 7 mm - 08 Imp 40, 7 mm Br (Benchrest) Remington, 7 mm Express, 7 mm IHMSA, 7 mm Mauser (7 X 57 mm Mauser), 30 Br (Benchrest) Manufacturer: Sinclair Manufacturer Number: Sin003695308