I have shot a few elk with the 308 (165 & 180 Noslers) and none at longer ranges. I tend to side with Royce on this one given the info and phrasing in the original post. BUT, let's just say you really want to and think you can make this work...
Find a 3/4 MOA (preferably better) load with the 190 VLD (try Re17) and put 100+ rounds down range each month between now and October, the majority from field positions from 200-600 yards - and if your equipment and skill allow you to be near 100% first shot hits at 600 in multiple weather conditions then, if your conscience lets you go afield and consider shooting an elk at 600... take a deep breath, know in your mind that you are capable... and then GET CLOSER.
