The J. Dewey Benchrest Style Bronze Rifle Bore Brush features premium "No Harm" bronze bristles designed for safe and effective cleaning of .50 caliber rifle bores.J. Dewey Benchrest Style Bronze Rifle Bore Brush"No Harm" bronze bristle constructionLooped brass core for durabilityBrass coupling with standard 8-32 thread.50 caliber bore diameterEngineered for benchrest shooters and precision rifle enthusiasts who demand the highest quality cleaning tools for maintaining accuracy and barrel life.