stagpanther, Hornady,Sierra,Nosler, manual have max 2.525" Sierra has trim 2.515". Hodgdon/Hornady have trim 2.530". I trim 2.515"
If you look at Hornady manual for 280AI they max case length for their 280AI case @ 2.590".
Most of my 100 Peterson cases are 2.5285" and my Nosler 200 case 2.5255".
I think alot got things mixed up since trim on 280 is 5.300". I got new Hornady manual coming see if the correct it.
If you fire form using 280 case you should be max @2.525" I check mine length that way.