A few observations: I've yet to meet the person who can eyeball the difference between 450 and 500 yards. Or 500 and 550.
I don't care what shoulder-held rifle you use, that 50-yard difference in being correct on the distance will cause a miss or a crippling hit on a deer or elk. For an '06. that 50-yard difference between 450 and 500 is a foot in trajectory. For the difference between 500 and 550, yuck.
If you're using a rangefinder, what difference does it make if you're using a .308 or a 7mm STW or equivalent? Or even a .3000 Eargesplittenloudenboomer? You KNOW the trajectory numbers, do you not? So you know the holdover or the mil-dots or the clicks and all that happy stuff. Me, I'd vote for light recoil in a lightweight rifle and carry that lightweight laser rangefinder.