I like all the Rounds Mentioned, But a mountain Rifle in 30,06 would be just fine as is. But if there is not enough barrel for the re bore you could probably find something to ,trade for.. Its surprising what you might find a good deal on in 06. I got into a pre 64 06 for 550,00 . Some body Refinished the stock and cericoated it before i found it. That might make a great 338,06. and they are not hard to find.
