unless u find someone with the old style dies... best bet is shoot some 280 brass through your rifle.. then send 3-5 peices to redding or others and get a set made!!! took me a long time.to find the 40 degree shoulder Ackley dies
Just by Lee three die set with a collet die for 280 Rem and you are set. the bullet seating die work for 280ai and you have a full length die for the standard case for fire forming loads.
Hornady has a set of 280 AI dies for a reasonable price.
I've got a three die set of Redding 280 40' dies that were priced a little over $100 at the time of purchase. Mine are for the traditional 280 AI chamber.