A 270 will kill an elk but don't even think about a 400 yd shot with it. If he is a one box a year shooter get him out to the range a lot before the hunt and tell the guide you want a 200 yd shot or better. My advice is borrow another rifle and practice with it, if thats not possible then get the best elk bullet that "Wal-mart" has. I think they even put little pictures on the box now that tell ya what they're made for. And please tell him to limit shots to 250yds, seen too many hobblin animals this year.