I recently bought an Investarms 12GA "Gallyon" percussion shotgun that according to the proof marks was Mfg in 1978 but I truly believe had never been fired. I tested it in anticipation of turkey hunting and was unsatisfied with the pattern (cylinder bore) even at 25 yards. I sent it off to Jim Chambers and he Jug Choked it "Full" my pattern when tested on turkey head targets, before and after went from about 7 pellets in the head to 34 (averaged over a multitude of test patterns). I did try the Skychief method only once, prior to shipping off but had the wad hit paper and shot was really spread out. Jim did a great job. I will post results of further testing as I get it done.