Well in my rifles opinion T7 was the dirtiest, Shokley's gold gave a decent fouling ring and had 1 - 2" flyers from very good groups, I used Pdex Sel as I get the most consistency out of it, American powder didn't work so well with accuracy with the particular sabot/bullet combos that I tried but was the cleanest, though it did show very good promise with a paper patched Lee .501 440 gr (need more testing on that one, the BHN is a main concern). I have never tried BP or the new Alliant substitute. IMO loose, it seems cheaper and easier to fine tune loads for your particular rifle/projectile combo if your wanting to get less than 2".
