The .308 is adequate for any moose or elk that ever walked, as, of course ,is the 30-06... On paper the 30-06 has some ballistic advantage, especially with heavier bullets, but in the field, at ranges that most of us shoot ( say 300-400 yards max) , it's not enough to argue about..
With proper bullets, the .270 is adequate also , but some folks consider it marginal for the big stuff, just as some folks consider the .243 marginal for deer...