Now you have opened up a can of worms mr. Call DMay and he will give you some pointers on what to shoot in that gun.
Don't shoot copper plated in a gun like that. Cast a 500 to 525gr bullet slathered in SPG lube. Find and order the book SPG Lubricants BP Cartridge Reloading Primer (Steve Garbe & Mike Venturino).
Welcome to the world of black powder. Wads, papper patching, BP compression, lubes, sights on the gun and many other things. Cleaning up after is very important. I have taken my Pedersoli: 1874 Sharps Competition (.45-70) out to 1000 wearing a Long Range 406 PED Soule tang sight with a hadley eye piece. Only load what you will shoot that month. Don't load to far in advance. Load friday night, shoot it all up sat & sunday. I have 3 45/70's. Have fun.
I also have 20lbs of Bees wax.