I have to agree with others here. Don't mean to be a downer, but unless that boy practices that shot at 600 yards, it was very irresponcible of him, and espeically the adults present. Just taking a poke at an animal is a sad state of affairs.
I do shoot long range. And I do practice over 500 yards, and without ranging the animal, and using either mildot or target turrets, I wouldn't shoot this far.