Thanks for the comments. I'm fairly sure the rifle and the (new) Redding dies were manufactured after the 280AI was properly recognized with its final SAAMI specs. The brass I use is Petersen 280AI, and I've never bought factory ammo for this cartridge. I guess a simple call to Redding to see if they want to make me a shell holder that is a few thousandths shorter would make it easier to get more bump if I ever need it.