Copper Chore boy strands (pot scrubber) twisted around a bore brush works well too.
I'll check if I can find some of that copper pot scrubber...sounds like the bomb
Or just find an older drugstore and request some "Blue Ointment" or Mercurial Ointment and patch some in your barrel, ....give it a day, and wipe clean!
Take a magnet with you. Lots of off brand ones are copper plated steel. Don’t want those. When you do find the copper ones, you want to wrap long strands around a brush so it’s a very snug fit in the bore. The edges on the copper strands will cut the lead out. Literally pieces of lead will fall out.
What do you guys use to de-lead your bores? I have an old 30-30 I bought used and it's leaded up pretty bad...
Last time I heard reference to "blue ointment it certainly wasn't for lead...altho it was recommended to clean a "dirty ol' bore"...nasty... LOL