They can "tune" a lever action to take other rounds. Also some times there is a burr that can cause problems. It can be one of a 100 things. Usually a good gun smith can take care of it.
Shot placement is everything! I would rather take a round of 50BMG to the foot than a 22short to the base of the skull.
all 25 of my guns are 45/70 govt, 357 mag, 22 or 12 ga... I believe in keeping it simple