Tom,
I'm not sure if you are the one who originally sent me link #2, but it was eye-opening and makes sense. Fire forming is a PITA, and I'd like to avoid it in the future (was hesitant due to headspace/SAAMI spec concerns). I'd like to run an experiment and post my results, but I'll need a LRH friend to help out:
I have a Cooper M52 in 280AI that Cooper swears was chambered to the "original"P.O. Ackley dimensions. I fireformed a bunch of Norma brass and that is what I am using to load. If someone is willing to send me one or two pieces of virgin Nosler 280AI brass, I will measure them side by side with my fireformed brass and post the results here. I will, of course, send your brass back (unfired, for all of you who are scam sensitive). If you are interested shoot me a PM and we'll make arrangements.