[Pathfinder45]

What Taylorforce said is true. I would choose a 270 and try to stalk closer. As far as the cartridges themselves go, the 270 is a higher performance caliber, but I doubt that a well hit deer could tell the difference. Individual rifles can vary a lot in terms of accuracy, especially at that distance. I think it takes a lot of practice to make a good clean, first-shot hit at that range, out in real hunting conditions. If I was preparing for a hunt like that, I would forsake shooting other rifles for a good while and devote a lot more trigger time with the one most capable rifle. And get rid of the bench rest too.
My 270 shoots most accurately at long range with 150 grain Nosler Partition bullets. So that's what I would use....in this rifle.