"If the shooter is capable of the shot"

That IS the rub isn't it. I worry that some youngsters out there in their "invincible" age may read your post and think they are capable of doing what you are doing. I havesuspect that you are capable of taking an ethical shot at that distance, but the other 99 out of 100 of us are not.

Here is a link to your ammo: http://www.federalpremium.com/products/compare/rifle_compare.aspx

Marginal energy at that distance means you will have to hit him in the boiler room.You may not get the job done with a shoulder bone hit. With the drop and wind drift (close to2 feet at600 yards in a 10 mile an hour wind) the only people who could reliably make that shot are those that have the time to practice, practice, practice and have an inate ability to shoot. Most of us don't have the time or the skills and never will. Is the animal going to take a step, is that wind 10 or 15 mph, how much above/below me is he, did my rangefinder give me an accurate reading, are all variables in an equation that leads to a clean kill or wounding/miss. I certainly won't say it is unethical for you to take the shot, but certainly it is for me and the vast majority of us.

And of course, the real question asked: Does it bullet have enough power to take an elk at that distance if thehit becomes marginal for whatever reason. If I am taking the shot, the answer is no.