Go with the 7 mm, thats what i use and works fine on elk. You can go with 160 gr part., failsafe or bear claw for factory ammo. A number of others two that will work in the 160-175gr versions.

If you do go with the 270 win look no further than 150 nosler or 140 failsafe...both bullets perform well on elk in our party, as 2 guys shoot 270' s on guy is a nosler fan the other isn' t