I generally try to limit my shots within 500 with my .308s on elk, and I really work to avoid shooting that far if I can help it. Conditions have to be absolutely ideal. It seems the 400s are pretty typical for the late season hunt. The 155 Scenar has proven to be an exceptional performer on animals for me.
Terrain can be an issue though and the elk have learned to spook at anyone even remotely close.
Here is a pic of my dad and kid on one of our cows from a couple years ago. We got lucky and caught some down low due to the temps. You could not get even sort of close to them, as they were spooking and running over ridge tops
Fortunately that day the herd split and some ran within 3-400 yards of us and we filled two tags in about a minute or so. I was glad we refrained from dropping a 3rd elk*, as it ended up being a challenge just getting those two quartered up and back to the truck. * My daughter is not comfortable shooting at moving/running game, so I have advised her not to take shots she is reasonably sure she can make. These were not high percentage shots for a young shooter, so she made the correct choice to just watch.
The primary reason I use my little 20" .308 is because it is very light and handy for climbing steep hills. When I think I am not going to be doing lots of climbing, I will use my .300wm as I prefer it for extended range shots. It is a pretty basic setup. A T3 that is in a Micky stock and topped with a fixed 10X SWFA mil/mil optic. I am quite comfortable with a fixed 10x, and actually prefer it for hunting in open country. I am currently in the process of doing some bottom metal work on the gun, so as to run an AI mag, in order to run VLD projectiles in the rifle.