Hunter......I have a Katy ported 45/70. I tried 4 or 5 of the IMR powders that were recommended. I also used 300, 350, and 405 grain Jacketed bullets. After several hundred rounds shot at 100 yds bench, best load was 47 grains RE7, 350 gr Hornady JFN, CCI 200 primers. This load should be about 1900 fps, and will kill most anything you care to shoot. I know for a fact it will blow through a 200 pound whitetail at 100 yards. Will be about 1.5 MOA at 100 yds in my Encore Katy barrel. Barrel may shoot better, but my eyes and steady hands are about gone. The encore barrel will take any load that the Ruger does. Anything above 50 grains of RE7, and the upper loads from IMR and Hodgen will hurt. Start low, work up, and when it starts hurting, quit, unless you have already quit because of a good MOA or bullets are sailing.