It would be real easy to 'do it all' with a 223 and a 300 Win Mag. But with a 30-06 already, there really is no need for the 300. But again, I'd consider carefully factors other than what the chamber digests before I worried about what kind of ammo I needed to feed it. A big rifle (338/358/375) is generally an extra unless you're specifically involved the the habitual taking of big bears - or you're just plain looney. (If the latter, you probably need to own at least one 308, 30-06, 300 H&H, 300 Win Mag, and a couple 30-30 levers - in different makes, of course; and that's just the 30 cal stuff!
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