I just got a new Uberti '76 in .45-75. I've been reading about forming the brass, but I'm a bit confused about the best way to do it. Apparently, it can be done from .348 Winchester, .50 Alaskan, .50-90 Sharps, and .50-110 Winchester. Some say you have to turn down the rims thinner, some say you don't. Is there one best way to do this? There are so many posting by guys who say, "Well, this is how I do it, because this is what I had on hand", but is there one of these four parent shells that is the closest to the .45-75?
ALSO; how can I tell if my rifle has the earlier, "oversized chamber", or the later "original chamber"? Is there a known serial number range at which they changed the chamber specs?