Otis Technology 5.56mm Chamber Cleaning Brush 367 is a multi-function cleaning brush that can scour the vital parts of your M-16, AR-15, or M4 rifle. This cleaning tool consists of a tapered bronze brush, a wider steel brush, and a cold-welded brass stem. The tip of the chamber brush is folded and allows you to scrub the chamber, neck, and shoulder of your 5.56mm rifle, while the steel bristles on this Otis Technology cleaning tool are ideal for getting at the locking lugs' star chamber. With a standard 8-32 thread, the Otis Tech 5.56 Bronze Steel Chamber Brush fits on to most cleaning rods, including Otis Technology's famous Memory-Flex cleaning rod. To liberate the chamber of your 5.56mm rifle from fouling and buildup, scrub away with the Otis Chamber Brush for AR-15, M-16, M4.