I have a RCBS case master? I think it's called? It does what I need afa measuring run out on cases and loaded rounds. IMO most runout happens during resizing. Some resizing dies just never produce straight cases. The worst I've ever had was a RCBS 204 fl sizer. Simply wouldn't make a straight case. I tried with decapping rod tight, loose, and gone altogether. Took them back and got Redding, then I had straight cases.
I've experimented quite a bit and some times with some dies having the expander button backed into the die closer to the top has helped some.
Then keep in mind if the necks are thicker on one side runout won't be good.
