NcSTAR 308 Chamber Brush. 308 Winchester Chamber Cleaning Brush TBC308 has been developed to be the perfect way to keep your barrel free of unwanted materials. Features of Ncstar Ratcheting Chamber Brush for Winchester .308: Ratcheting (GI style) Fits into .308 WIN chambers Plastic Ratcheting Gearing Use GI cleaning rod to quickly ratchet the chamber brush Package Contents: NcStar Ratcheting .308 Winchester Chamber Cleaning Brush TBC308 NcSTAR 308 Chamber Brush TBC308