I was rather fortunate in restoring my M1860 Spencer Rifle, which the barrel had been cut-down to carbine length (22-inches), that when I spoke with Larry Romano about what he recommended -- whether to reline and stretch the existing barrel back to full-length or replace it with a new-made 30” barrel -- when Larry recommended the latter course of action was when he further made the suggestion I should have the new barrel chambered in .56-50 to make it easier to reload. So when he built the new barrel, he sized the rim of the chamber to permit use of both cut-down .50-70 and Starline brass, interchangeably.
Because the outside rim diameter of Starline brass is slightly smaller than .50-70 rims, some blade extractors may not work properly and lead to extraction problems. I haven’t had any such problems, and because I haven’t had any such problems, when I decided to order more brass, I ordered a thousand Starline .56-.50 cases to get them at $0.88 per case (if once fired). If you are crafty, and you don’t crimp too tightly and fire-form your brass, you can reload the same cases for as many as five times (or more) and essentially reduce the cost to just $0.18 per case.
While you can reload for as little as $0.572 per round using Bell .50-70 brass from Buffalo Arms, you can reload Starline brass for as little as $0.40 per round. That price includes not only the outlay expense for lead, brass, powder, primers, and lube, but also includes the expense of a lubricizer and reloading press (with dies), all prorated over a 20-year life cycle (or an estimated 30,000 rounds). Total cost of reloading equipment (i.e. bullet mould, reloading dies, a sizer and top punch, lubricizer w/ heater, and reloading press), can be had for under $500 if you shop around.