Flat nose cast .458 bullets work from 1300 fps at the muzzle to around 2000 FPS in my opinion. You can run them faster but there is no real benefit on hunting loads. Alloys from 10-12 BHN up to 19 or so work great as long as the hard ones are not brittle. You have to have enough arsenic and Antimony in there to toughen them up. I prefer the softer ones myself. Most of my loads are between 1650 and 1900 fps, weights from 433 to 490. All of them kill whitetail about the same. No problem hitting where you want to at 250 yards as long as the shooter does his part. I shoot almost all my game sitting over sticks. Shot my buck last year offhand but he was the first in a while that way. Powders that work well for me are AA 2015, the old IMR 4759 which I still have a lot of!! and going to load some up with AA 2460 this year. Proven by Sir Ron as a good cast powder in the 458WM. Search this thread and you will find! All of those should be good in your Howell as well.
