Smyth Busters: Are Bronze Brushes BAD for the Barrel?

Today's bit of Internet wisdom, what the mythical "they" are saying on the forums, social media, and even in comments to Brownells videos, is that a BRONZE bore brush will damage your gun's STEEL barrel. Sounds like a topic tailor-made for the Smyth Busters, doesn't it? Caleb thinks this idea came from somebody cleaning their barrel with a bronze brush, then inspecting it and discovering factory defects in the bore. Steve theorizes another cause of damaged rifling: shoving a bronze brush down a .22 rimfire bore using a 3-section, steel M16 cleaning rod.

There's no way a soft metal like bronze can damage a modern steel barrel. Now, the steel on old pre-1900s barrels MIGHT be soft enough that you could wear it out with excessive cleaning, especially if there's a lot of burnt powder in the bore. The powder residue could act as enough of an abrasive to attack the shallow rifling. But even then, you won't tear chunks of metal off the bore! Also be cautious of a bronze brush with a steel wire core. If that core scrapes the muzzle crown, it can cause damage. For extra safety, stick with brass-core brushes.

Uncle Steve's Advice: Don't clean your .22 rimfires any more than you absolutely have to. What would happen if you put a bronze brush on one end of a cleaning rod, chuck the other end in an electric drill, and really go at a dry bore? Cousin Caleb tells us about it.

So that myth is BUSTED. Go ahead and clean that bore with a bronze brush. When the rifling wears that brush down to a nub, get a new one. If you want to be extra careful, use a good-quality bore solvent and a NYLON bore brush. Even better, use a BORE GUIDE to protect that rifling. If you're using a steel cleaning rod, be careful to keep it from scraping the rifling.