Otis 338/35 Cal Bronze Bore Brush

One brush covers two bore sizes here, 338 and 35 caliber, which share close enough dimensions that Otis builds them on the same head. Phosphor bronze bristles pull carbon and copper out of the rifling on a magnum rifle barrel without scratching steel.

The brass stem is stamped with the size, so it stays identifiable after it has been through a few cleaning sessions and lost its shine. Standard 8-32 threads fit Otis cables and conventional rods, so it drops into an existing kit. Follow the brush with wet patches to carry the loosened fouling out of the bore.