I shoot a 150 Etip out of my .308 at around 2700 fps and have had great success on mule deer out to 300 yards. Speed is your friend with copper solids. For terminal performance minimum impact velocity is far more important in getting them to open up than ft/lbs of energy. I would not have a problem shooting an elk at 300 yards with my .308, I'd say your combo would probably be in the same range.
I am still working on a load in my 7mag with 150 Etips starting around 3150 fps and I would not be too worried about shooting an elk at 600-700 yards with that load. Should not get down to the 2000 fps minimum velocity for expansion that I am comfortable with until you get to 700+ yards in typical elk hunting altitudes. That's all based on computer models, killing milk jugs and a handful of mule deer. Haven't had the pleasure of puting one in a elk yet.
