I bought an -06 for my son when he started hunting. Huge mistake!!! You couldn't hit the ground in three tries. I have friends who own them in 223 and 243 and love them. I know a guy whit one in 280 and he hates it.
My pure speculation is that the rounds that throw heavier bullets faster, 30-06, 280, maybe 308, torque the action as the bullet travels down the barrel. (stop me when I get too technical) After lots of trying with the -06 I finally got a load to shoot into about 3 1/2" at 100 yards. Great.
When I bought that gun I had great plans for; I was going to make it mine; then I shot it, change of plans. I couldn't give it away fast enough.
I guess long story short; if you are getting the 243, I have heard good things just stay away from the bigger calibers.
Good luck.