I've killed a couple at about that distance with the 300 Win Mag.I can tell you that it kills them,and pretty quickly,too with a solid chest hit.
I have seen the 30/06 used at about 375 yards;it killed them,too.
I would not want to get in the way of a 30/06 slug at 450 yards.This is anecdotal,but a reliable friend reports using the 30/06 in the SanJuan's with 165 Partition,and being faced with one of those last day "do or die" situations at about 500 yards,stuck a 165 Partition from his 30/06 into the base of a bull's neck as it quartered away a bit; the bullet traveled up the length of the neck and blew out near the head.This was,of course,a very dead elk.
I know the rifle, the shooter,and the load,since I helped him work it up; he was no doubt very lucky that day,but it impressed on me that the 30/06 is no toy,and likely better than many people who shoot it.
