I, too, have an 8mm countoured blank lying around. My intent when I purchased it, was to rebarrel a Ruger # to .325 WSM. But then Winchester came out with the 1885 in .325 WSM, and I purchased one of them. I even had a #1 in .300 Winny to use for a donor.
Thus, I just shelved the idea.
Recently, I purchased a set of 8x68S dies on ebay. And coupled to the fact that I have 2 or 3 boxes of new, unprimed brass, I think that's what I'm going to do. The next hurdle is to find a reputable 'smith with the reamer. Once that's accomplished, I suspect, it'll be a done deal!