600 yards is a chip shot for a practiced long range .308 shooter. The right load can deliver plenty of power to same distance.
I've put 10 out of 10 in the black from 500 meters(550yds) with iron sighted rack grade M16s, shooting milspec 55gr ball.
An accurate, heavy .308 with sniping optics is easy money at 600 yards. I've made 600 yard headshots on paper human targets with boring consistency, using heavy Rem 700 and 168gr Federal GMM ammo.
I reiterate:
proven load
practice
laser RF
passing on iffy wind.
Now, personally, I'm not a long range game shooter. I've never shot deer past 200 yards. Likely never will. That's my personal choice. The intent of my first post was do call attention to a particular bullet that can eek out plenty of 600 yard killing power, via a "sniper" .308 rifle.
I'm not advising the non-practiced, once-a-year rifle shooter to grab his walmart rifle, 4X Tasco, and Green Box of 150gr CorLokt to eagerly go forth and sling lead at 600 yard deer.
