Thanks for the reply, Ron.
I scrubbed the bore using copper wool and even made a groove scraper out of a wooden dowel and the staple from a cardboard box to get rid of all the flakes. Then I fired some jacketed bullets. The bore is not perfect, but it is now clean.
My next loads had Alox coated cast bullets with the grooves filled with 50/50 beeswax/shortening. At 50 yards I'm now grouping about an inch with no leading.
I also switched from AA 5744 which left a lot of unburned grains to IMR 4198. I use a piece of cotton to hold the powder back since the case is so large compared to the powder charge.
My next experiment will probably be to use 65 gr of FFg black powder.