Here's an amateur (very) video of someone using a forming die set to change 8X57 Mauser to
8X56MS.

YouTube

It seems like a lot of steps. I have had excellent results using a standard RCBS two die set and a Lee 'C' press to reform and load 9.5X57 from .35 Whelen. I cut them to 57mm after forming the shoulder in a single pass, then loaded. 'Easy peasy'.