.243, Hands Down
The .243 is a hard hitting, low recoil, and accurate round. It is more accurate at 400 yards than the 30-06. It is a great round for deer, because it doesn't recoil much at all, and has the power to drop a deer. The Ruger American Rifle is a great rifle, and has a very smooth action. I tried the action of a .243 Ruger American Rifle and it was a nice short, smooth action. .243 is definitely what you want to start out on. Hope this helped and let us know what you decided on. They are all great rounds, but the .243 is what you need to start!