I would say a 338 Win. Mag, 300 Win Mag, or 300 WSM would be the best options for a moose rifle. Lotsa power and they shoot flat enough to do a 300 yard shot. If you want to use the rifle for deer hunting as well, i would lean towards the .300's as the 338 is kinda big for deer. Nothing wrong with a 30-06, however i would personally like to have a little more power if given the choice. Accuracy is still the most important factor. If you don't want the extra recoil and can shoot the 30-06 well, it's more than adequate.