dcali
Bullet Maker
KG12 is the best copper solvent I’ve used. Or maybe sweets, but that stuff is murder on your nasal passages. That said, I have never seen the need to break in a barrel. Every custom barrel have ever owned has shot fine from the start and had minimal fouling. Factory barrels are beyond help. You get what you get and spending lots of effort on one seems to be penny wise and pound foolish.