When I looked at the OP's first post, I noticed he mentioned "for whitetail deer" and for that reason I would rule out the 22-250. Heck it's most likely not even legal in most states as a deer cartridge.
For that reason, I would second the 243. Ammo SHOULD be a lot easier to find, and it's a solid 300yd deer round. You could even get an 8 twist barrel and go with some of the Berger long range bullets and put a real smack on yotes and just about any distance you chose.