The primers look to me to be about right considering the bolt face, look at it you'll see. It's likely not beautiful itself. If they were FLAT, it would be because of high pressures.

The swelling isn't a problem, look at your .45 cases sometime... As for case shape, it's still different from the .351 by just a bit.

Won't cycle because of bolt weight...yes...needs large transverse holes in the slide up front. Mine ejected 9mm completely. Also if you can polish the chamber a bit with fine machine paper and oil you'll be gold. There's a bit of roughness on the cases...I think.

You'll want that mag fixed forward so the cases are controlled into the feed...