Ballistically, the '06 and 308 are so close as to not make any difference. Since we are talking about a tip openm single shot, action length has no bearing on the subject, the guns will weigh the same and handle the same, it is a question of personaly preference. But if you have a 7mm Mag, there is nothing that either of these give that you don't already have. A 243, 25-06 or a 35 Whelen would offer a better ballistic balance to your battery.