This is a Birchwood Casey Brush known as the Chamber Brush, model BC-41285.
Since 1948" serious shooters" avid collectors and professional gunsmiths have relied on Birchwood Casey for shooting and gun care products that have stood the test of time. Birchwood Casey has pioneered innovative products with an unwavering dedication for quality.
Features:
Steel Bristles at the Base Scrub the Star Chamber/Locking Lugs
Bronze Bristles Scrub the Chamber