I had some 8x57 that I had made from 30-06. I just necked them up, no neck turning to speak of. There was zero resistance in getting them to chamber. I know a lot of these old 9.3s suffer from having the chamber cut too tight in the neck area, but that doesn't seem to be the case with mine. We'll have to see if that holds true when I stuff some cast in it.
I'm using Hornady custom grade dies, and they have quickly become my favorite set.