Yes I would stick with one of the tried and true. 270, 30-06 308 7MM Mag or 300 Mag.
I don't know how many elk I have killed in my 56 years of hunting them, but I have owned and used several of the new hot fast super mags. And you are correct. Out to about 500 yards I can see no real difference is the quickness of their deaths between a 270 and a 7MM STW or a 300 Weatherby.
What I can and have seen is the difference between bullets that break apart badly and those the hold together well.
