The way I look at it is that the '06, loaded to the same pressure, and often even less, will always be capable if out-performong the .308. However, with current powders, the .308 can equal or even exceed standard factory '06 speeds, and really beat the original velocities the '06 made its reputation with way back when, at least with light to middle weight bullets. New bullets help even more. To me, it just makes sense to match the cartridge to the action you're using, or even as in my case, the pile of brass you've got on hand.
