BoreSmith, Cal 357, 9, 380, 38 Special, Pistol Bore Brush, Nylon Our standard brush has nylon filaments, and it is made for pistol/revolver length chambers Standard 8-32 threaded connectors are made of non-abrasive aluminum Carbon-steel twisted core wires give our brushes superior strength that resists bending Packed in heavy duty plastic tubes for safe and easy storage Nylon filaments do not react with ammonia based solvents to discolor patches Our standard brush has nylon filaments, and it is made for pistol/revolver length chambers Standard 8-32 threaded connector is made of non-abrasive aluminum Carbon-steel twisted core wires give our brushes superior strength that resists bending Packed in heavy duty plastic tubes for safe and easy storage Nylon filaments do not react with ammonia based solvents to discolor patches