I'm not gonna say it can't be done by hand, but that's a lot of metal to remove by hand, not to mention the expectation of it to stay nice an concentric, I spent almost 3hrs doing a 44mag to 444 Marlin and still ended up having to use a ½" drill to finish it up, my blistered, gloved hands were just to painful to finish it!
I wouldn't recommend doing the 357mag to 356 Win by hand.
Pete's having a friend do his on a lathe.
Tim