I would say that the 270 is a little on the small side for elk at 300 -400 yards. ( I am not saying it is a bad round) I would go with something with a little more down range energy 300 win mag or 300 wsm (If you like them short fat dumpy looking things) I would try to go with something that you can get ammo for just about anywhere you never know what might happen on the trip there. If you hand load I would work up a good hunting load with a 180 to 200gr bullet. Then I wouls also find a factory load that will shot the best in my rifle that way I am not going to be unknown to the factory ammo I am shooting if I happen to lose of my handloads get damaged in any way.
You could always go with a 7mm mag or a 7mm STW (Shooting Times Westerner). Now that aby shoots like a laser beam lots of speed and flat shooting for 400+ yard shots.