Originally Posted by B23
What about 243ai since you most likely already have 243 brass and if not you can buy Lapua brass and 100-200 pieces of brass will out last the barrel. Also, in my opinion, a 243ai is a better fit for a short action than is a 6-284. My 6-284 is on a Rem 700 short action and if I had a magic wand I would turn it into a long action.
the real problem with a .243AI is case shrinkage during fire forming. The neck is already too short for good barrel life in the generic .243, and then you'll shorten it another .03" to further aid throat errosion. I'd suggest you look at doing a .243AI reamed short off a 6mm AI reamer. This gives you everything! The longer neck for better seating and barrel life. Cases are easilly formed from generic 6mm brass, or even .257 Roberts brass. Ford load data yousimply use .243AI data, but you end up with the better neck and shoulder angle.