These scopes are for 308 match ammo, I beleive 168 (might be wrong,but I dont think so). Springfield Armory used to run a deal with these scopes when you bought a M1A.You got the scope, 2nd gen scope base,and rings, for about $225.00. I bought my rifle and scope package around 1999 or 2000.
There should be no reason you coldnt get it sighted in for yout 243. the only problem you would have is the bullet drop figures wouldnt match up.