AtlLaw, your trevails were the reason for a road trip to inspect before purchase. My cylinder arbor is perfect, when bottomed out the barrel assy, twisted sideways, is exactly flush with the frame. The one flaw, my loading lever latch blew off, so I now have a tiny Colt Walker with a twist tie around the barrel. A gunsmith tried to punch it back in, but it blew off on the first shot, I think he will have to sweat it on or something.
So far, I have tried CCI 10, 11, Rem 10, 11, and Dynamit nobel 1075 (?). The DNs blow fire out the barrel! Rem 10s are long and snug, CCI 10 and 11 fit so snug I can't seat them all the way and have misfires. The problem, all primers blow off, blow the hammer back, and drop in the hammer recess. I read here before about weak main springs (?), Treso nipples, and will search back posts for info on this primer jamming topic. I know they wouldn't have put up with this in 1862, so I will persevere.
I had better groups with 15 gr, laboriously hand measured, but found a pretty CVA measure that throws consistent 20 gr, so have been using that. With wad, ball is just below cyl mouth. Penetration 1/2" or so in 2x4s. 8" or so groups at 25 yd, 20" high. All charges 12-20 gr blow off the cap.
I love this gun, I will continue to work with it. Thanks Nobade, StrawHat and ugly cat for suggestions and encouragement. It took many pleasurable hours applying the knowledge on this board to my Colt 1860 Army to be able to plink cans at 50 yd, and I know I will master my Police.