I'd get the .243 barrel. Nothing wrong with the .243, those that say a bigger cartridge is needed are usually poor shots or don't have a clue as to what they are talking about.

Other option- buy a Lee Loader and start reloading 30-06. A 30-06 pushing a 150 gr. bullet 2400-2500 fps isn't going to recoil much, will shoot plenty flat for your hunting situation, and will have plenty of energy to kill a deer