OTIS BORE BRUSH PACK .260 CAL./6.5MM 2 PK. Otis brushes have a proprietary Tufcor core wire that is corrosive-resistant with a tighter twist for better bristle retention and brush life. These brushes clean .260 cal/6.5mm, .264 cal firearms, are 2” long, and fit 8-32 threads. Includes one nylon brush and one bronze brush.