Semisane, I have found through a lot of trial and error that about the best soap for real black powder, I pretty much exclusively use Swiss, is that cheap Ajax dish soap. It seems to work the best of all of them. Dawn comes in a very close second. One little trick I ran across that makes barrel cleanup just a tad easier is to dry swab 2 or 3 strokes before you go to cleaning. Getting that layer of ash out beforehand seems to help a good little bit.