Going back to the comment "what would 500 kill that a 416 couldn't?"

It's simple, any experienced DG hunter can tell you, that a 500 is far more a killer and effective than a 450 and a 416 and a 375 etc.

And if hunting in thick cover or a wounded DG beast, a 500 is an obvious better choice.

And if hunting elephant an obvious better choice.

A 416 is a compromise rifle. A good clients rifle. Better for plains game by far than a 500. But a 500 is far better for DG.

On the good old days one would have both. And call for the 500 from the gun carrier when needed.