Glad to see you made it over here where the data and experience is. Sir RifleCrank has written and documented a vast amount of 458 knowledge around the Square Table as he calls it.
I have a Whitworth 458 that I bought in about 1982 or so, shot 500 or so full patch 500 Grain Hornady Solids through it for a "learning about the .458WM" phase in the first year, and then have been shooting it since with a few more full patch Solids, several hundred jacketed 405 Remington's, a hundred or so 400 Barnes original SSP and lot's of Cast Gas Check bullets. Like RifleCrank mentioned, it is nonsense that the .458 won't hold accuracy over many rounds, well proven not true. The big bores are not prone to Throat erosion and the rifling's don't wear out from bullets passing over them...so that is the science of it. I like Cast Loads for hunting but you might like a Barnes 300 TSX at 2500+ FPS. You can find the data for both here in RifleCranks writings.
