Nice -looking rifle, but as one poster has already noted, not the best cartridge. IMNSHO, you should not use anything but BP in that original action. The cartridge capacity is somewhere between 100-120 gr., depending on how deeply the bullet is seated. To load "only" 80 gr. BP, you will need a wad stack to avoid airspace. That can create its own challenge in creating an accurate load. Even a full-power load is far more difficult to achieve in such a long cartridge than a .45-70 or .45-90.
In addition, the rifle is far too light for comfortable shooting. I have a Shiloh .45-70 that weighs 10 lb.; loaded with a smokeless load, recoil with a 520 gr. bullet at 1350 fps is more than I want on a continuous basis, although it's a great killer. Your 8 lb. rifle will have vicious recoil with any except the lightest loads.
If you use it for hunting, you should be able to develop a load with a 400 gr. bullet, lots of filler or a wad stack, that will be suitably accurate. Since you're not shooting it a lot, the recoil shouldn't matter; I never feel the recoil when I'm shooting at game.
Clarence
