De-Leading...
One of the best tools for that task is the aptly named "Lewis Lead Remover", from Midway or Brownell's. It really does the job and will last for years, and all you do is replace the brass "screen" patches, as you use them up.
Or, as a cheaper/faster alternative...
Find an all-copper "Chore Boy" pot & pan scrubber at the supermarket. I say "all copper" as some are just copper-coated steel -- so bring a magnet when you shop! I did use those cheaper ones once, and they worked OK, but now I use the all copper ones.
You simply unwind the Chore Boy and cut a 2x2 or 3x3 patch and push it through the bore with a standard bore brush. The copper "coils" really do a great job of getting the lead out.
Others will be along with their favorites too, but these 2 work the best for me.
Tight groups,
Old No7