About 20 years ago, I picked up an 1859 Sharps saddle ring carbine and original “50-70” carbine rounds. I believe the cartridges were 50-50’s. My carbine was one of the Civil War 54cal paper cartridge/percussion cap models that was converted after the CW to 50-70 center fire. Still has it’s Maynard tape primer system. I cast bullets for it and fire it with TrailBoss powder. Shoots great. Only paid $725 for it. It had been refinished, but still a pretty good deal. Also have 1860 Spencer 56-56. Easily installed center fire breech block and enjoy shooting it. 50-70’s are easy to reload, but the 56-56 Spencer with the original heel-seat bullets are a little tricky.
Trail Boss also works well for my 458 Lott reduced power loads, 350gr lead Laser Cast at about 1000fps.