It could be done easy enough, but won't be cheap, and it's one of those things you'll be well advised to get the brass on hand before starting the project.
I do agree. Getting the Brass and components to load and shoot is everything.
I cannot find that such exists, seems like it would be a cool rifle if it can be done. Does anyone have any experience/thoughts on this?
Didn't see anything on the 50-70 cartridge in an original Winchester survey by William Porter or by Bert Hartman. Being one of the first true original cartridges adapted by the U.S. Military in the late 1800's I was a little surprised to see none we're recorded as mfg. by Winchester for their S.S. High Wall Rifle. The 50-95, .50 express, .50 straight, .50 Eley, .50 E.E., .50 Eley, .50 Eley Express, .50 3 1/4, .50/90, .50/95, .50/95 Express, .50/100, 50/100 Express, .50/110, .50/110 Express are all in William Porter's Winchester Survey as a Winchester employee Curator.
So there are options naturally and with that many to choose from I wouldn't ruin an original High Wall unless it was truly worn out or spent so to speak. Then I could understand it. I like what tmitch did using an aftermarket improved CSA S.S. and going for a .50 caliber of his choosing with a better chance of Brass and components to shoot. Remember the original Winchester High Wall S.S. had an improved weak wrist design and when John Moses Browning invented the Original S.S. design that Winchester bought the patent rights to it took them approximately 5-6 years to improve on the original design and to this day as we observe the larger caliber Winchester S.S. Rifles many have slight cracks in the wrist area weather it's a hairline crack or a larger crack or split in the wood as on many occasions have been repaired. I can truly appreciate you're interest and wish you the beat in pursuit of an extremely historical cartridge but I've had different desires over the years and for me a more desirable cartridge in a more ballistic cartridge might be considered. In contradicting myself do what makes you happy! IMHO!
HS 58