Tipton Nylon Bore Brushes 243 Caliber/6mm Rifle, 3pk These Nylon Bore Brushes clean while protecting the bore from abrasion. All brushes have 8 x 32 male threads except the 17 caliber which have 5 x 40 male threads. Features:- Fits: All 6mm and 243 Calibers- Nylon Bristles (.278 Diameter) Unaffected by Ammonia based solvents.- Galvanized Plated Wire Core with Looped End and Crimped Coupler.- Thread: Standard 8-32"Note: Will Not Fit Outers Cleaning Rods.