WOW!! Nice rifle!
I have the Pedersoli Sporting Sharps in .45-70, my buddy has their Billy Dixon .45-90 and Rolling Block .45-70.
"Experimenting' is half the fun with these rifles but your "revelation" will come with Holy Black and lead/tin bullets.
I pulled my hair out trying to get my buddy's '90 to shoot with wheelweight bullets and smokeless powders. My "best" smokeless loads would print 7"-8" patterns rather than groups AT 50 YARDS!!! Switching to "real" powder and lead/tin bullets was "eye opening' to say the least.
Go ahead and order some Goes from
www.powderinc.com A pound doesn't last long feeding one of those, and you can order as little as 5 lb at a time. Best price is on a 25 lb case.
I tried Goex Cartridge grade and the only difference I noticed was slightly less velocity and another $1.00 per pound on the price. Fouling wasn't noticeably decreased and accuracy wasn't increased.
Accuracy did, in our cases with all three rifles, improve as velocity and bullet weight increased. In my .45 -70, 70 grains of FFg compressed .400 under a slightly "undersize" Ideal 457125 lubed with 2/1 beeswax/Bore Butter has been my best load.
Start making weekly trips to you metals recycler in search of lead sheeting, pipe, cable sheathing, and commercial ingots of plumber's lead. Stay away from "mystery metal" someone else has cast into ingots except for use as plinking pistol or rifle bullets.
Let the white smoke roll!!!!