This question comes up a lot.
In response I've been trying to direct people to this article
http://www.gunsandammo.com/2013/09/1...-hunting-bill/
Read it and you'll read about the short comings of the 308.
Personally I think the 308 is fine for most game up to 400 yards.
Download the ballistics calculator that Federal has and you'll see that the
308 is down to about 1800 fps and 1500 lbs/f energy which is about minimum
it needed for a reliable expansion of most rifle rounds.
What I like about the 308 vs 30-06 is the slightly milder recoil of the and
308 and what I like about the 30-06 is the amazing selection of bullets and
if you do your job it gives a quick kill for 99% of game in N-America.
Ideally just get both.