my hunting partner and I shot a truck load of 70's of all flavors in custom 243 AI's with zero freebore. I fireformed with a load of 47-47.5g of Win 760(AA2700 great also). Formed loads I shot 380-38.7 depending on the barrel.
Brass was Rem 7/08
CCI 250's
70g, customs, TNT, Ballistic tips
Velocity was 3800-3850
Accuracy in the 2's or smaller
Don't forget to try other bullets, 75g V max may not like your barrel. 70g Sierra Blitz king would be my second try.