I think the nod goes to the Lapua among the rounds mentioned based on quality of brass available, but any of those rounds would do fine on elk out to 800 yards I would think. I have a 338 RUM in a sporter weight rifle but I am getting ready to do some work with a 28" heavy barreled 300 RUM in a McMillan A2 stock. That is going to be my long range elk rig for stationary sit and glass hunts. 200 gr Accubond at 3200 fps with a published B.C. of .588 is pretty impressive for a hunting bullet.
Killed an elk in 2008 with that load at 589 yards. Through both scapulas and as far as I know the bullet is still flying!
