Dan, I have done a bit of informal testing with my 45's, the ones loaded with a wad will consistantly shoot cleaner, less fouling than without. I understand that the fouling occours behind the wad, so I have no explanation other than the possibility that the extra compression may help but I've tried this with different amounts of powder/compression and the results are always the same, with the wad runs cleaner longer. I must admit, I have never put smokless powder in a 45 Colt, so I can't help there.