KleenBore military-style brushes are designed specifically for M-16 AR-15 AK-47 and similar rifles. The chamber brush is configured with two diameters; the first stage of phosphor bronze cleans the chamber while the second stage of stainless steel cleans the bolt-lock area. The chamber brush is configured with two diameters; the first stage of phosphor bronze cleans the chamber area while the second stage of stainless steel cleans the bolt-lock area Features core wire looped through a brass coupling that is threaded at #8-36 Please note the #8-36 thread is not commercially standard but will fit most KleenBore multi-section rods