Get the .30-06. Everyone should have a .30-06 in the gun cabinet.

Most people acknowledge that the .30-06 is suitable for taking any North American game. The .30-06 has taken many grizzlies and brown bears, even though heavier cartridges are commonly preferred for these dangerous game species. You should not feel undergunned hunting Elk or Moose with the .30-06. There is less confidence and assurance about recommending the .270 for these same animals. The .30-06 is the most commonly available centerfire ammunition. You can find commercial loads for 150, 165, 180 grain bullets and perhaps also 220 grain bullets. You can find lighter weight bullets also I'm told.

One advantage of the .30-06 is it can be used as a back-up for any hunt. If you want to hunt moose with your .338 Winchester magnum, great choice . . . take your .30-06 as a back-up in case the .338 gets busted up somehow. You want to hunt pronghorn antelope with your .25-06 or .243, great choice . . . take your .30-06 as a back-up in case the .25-06 gets busted up.

The .270 is a fine cartridge, but most people will concede the .30-06 is more versatile. This doesn't mean you can't have other cartridges, you should. It doesn't preclude having both a .270 and a .30-06. If you don't have either, my advice would be to get the .30-06.