I have fired several originals all infantry versions and a few sporterized jobs. Trap doors started out as breech loading conversion for Muzzel loader. The originals shouldn't be shot with any thing other than duplication of BP loading. Most cases they do best with lead bullets. Factory loads had be geared to allow using them in the old BP rifles. With
45/70 making a big comeback and all kind of buffalo loads being sold, be careful what you are shoving in it.
Thought I remembered something about the cavalry using .45-55 ?