I was thinking "practically" here guys - that's why Doubles chambered for the 450NE or 470NE both make sense. Am I allowed to use the word "practical" and "double rifle" in the same sentence?? :)
If I truly had my choice, I would prefer be 577NE I suppose. John "Pondoro" Taylor held it in very high regard for flat out stopping an elephant in a charge - even with non-fatal bullet placement - so that a follow up killing shot could be made. He said, and it makes sense that it would penetrate better than the 600. Too bad the 700NE never existed back in the glory days of Elephant hunting to see how it would have compared.
I have a 460 Weatherby that would likely out penetrate any of them but it will never have the style or class of a double.