That's something I've got to try Bronko. I've shot a ton of 300 grain .458 Speer hollow points with MMP sabots, but never any 405 grainers.
Years ago I got a good deal on a whole bunch of those 300 grain Speers, so that's what I used. They shoot pretty well. But I've always suspected the classic old 405 grain might be even better. I know the heavier ones are more accurate in my 45-70.