Interesting. The 40-70 Win was a strange duck actually a shouldered or BN case.
(You need to Login or Register to view media files and links); I do not know when it came to being or when it was discontinued, but you certainly do not see mention of it very often. This seems to be one of those "in between" cartridges and difficult to find much info on. If a 40-70 SS will fit (length would be a problem here as it is .100" longer than a 40-70 Win), and it should go easily (dia wise) if it truly is rechambered to 40-70 Win, and a 40-65 will fit, more snugly, then it most likely is a 40-70 Win and not a 40 2 1/2, a general description for a sharps straight, because neither of those cases 40-70 Win or 40-65 Win, would fit in a 40 2 1/2" chamber. A 40-70 SS could have been rechambered into a 40-70 Win I believe, but there is a significant difference in bore dia for the two cartridges. The 40-70 Win was most likely for jacketed bullets, not lead so I don't know how that would have worked unless the barrel was somehow rebored. Meacham was well known for reworking rifles and this most likely could be the case here, Is there mention of Meacham imprinted on the gun anywhere?
I once heard of a simular find in the juniper and sage lands of eastern Oregon, in the country east of Bend. Gun was found leaning up against a tree. Wood was shabby but all there and the gun although rusty was not in to bad of shape. Gotta wonder how they wound up where they did??
Anyway,,,Great piece, great story.
Enjoy
Cary