The 270 and a good 150 gr. bullet will work if you do your part and take broadside shots at reashonalbe ranges up to 300 yards. I used it for years when elk came out on the open slopes in Colorado in the evening and it worked with both 130 and 150 gr. bullets equally well.
Where I hunt elk today in the black timber swamp holes of Idaho I have seen a lot of elk wounded with the lighter rifles as all shots are going away from the hunter in very thick growth, so I went to the .338 and 300 gr. bullets or the .375 and 350 gr. Woodlieghs and that puts the elks nose in the dirt with a going South shot..Another benifit to this is my elk don't go to the bottom of the drainage where getting them out is pure hell....
