I agree with Mac 100%.
Ken
If you have either the 270 or 280 I'd leave the other two home for elk and use whichever of the two larger ones that shot the best.
With the heavy bullet weights the 25-06 is no comparison to the 270 or 280. Oh sure the 25 will kill elk, so will the 243 but neither as consistantly as the larger ones. Due mainly to heavier weight bullets.
Again, given the choice of the two you first mentioned, go with the 25-06 and a 120gr Partition or similar.