Apart from what fredIII said, I think you are off to a good start by asking yourself the right question of bullet terminal performance in case of good hits.
Playing your load in QL, I come up with two observations:
1: OL seems to think your load is way up there in pressure, right smart against ´SAAMI max.
2: Taking a minimum velocity of 1800 fps at impact, your load would reach this at around 475 yards.
To 1:
I have no idea of COAL and other factors nor of your load data, so here you are left to your own devices and this is mearly a quick and dirty QL proxy.
To 2:
1800 fps is given by Nosler as the minimum optimal impact speed for the Partition (
http://www.nosler.com/partition-bullet/), so this is a good starting point.
My own experience hunting elk is somewhat limited. For what it is worth, hunting elk in the Colorado rockies with my hostdad and a study term on elk in the Alberta Rockies lead me to believe, that a .308 Win. with a 165 Partition is a fine elk rifle. Myself, I would limit my shots and fully expect to get a cow well inside 300 yards.
Elk are, where you find 'em. When you have them getting set up close is usually not the problem and the work begins when the elk is down. This last is also good to have in mind before one drops an elk way down at the bottom of "Bottomless Gourge".
Best of luck on your hunt.
