The 308 is a very common round here for elk, which you can see walking down the street here from time to time in the winter. The 150-165gr bullet is plenty for well placed shots out to 3- maybe 400yds but not really any more than that. That 600yd shot seems to always come at dusk and that probably means a long night of tracking unless your really good.

Armed in Utah is correct that elk are tough and placement is the key with that caliber. Another thing is that if you want good groups while breaking in that barrel don't use mil-surplus 147gr bullets, use what you will hunt with.