Hi atlasman,

If you are intending to have only one centerfire rifle to do anything in North America....the .30-06! (Actually, you can find ammunition for the .30-06 worldwide.) It is the quintessential "single rifle battery"!

You'll find ammo for it anywhere. You'll find it inexpensively....because it is so common. And you'll find it in very differing loads to tailor for its intended use. It is the most common caliber for a very good reason!

Best of luck with your decision!