The 458 Win gets 2150 fps with a maximum compressed load of temperature stable Varget or 2160 fps with a maximum compressed load of temperature stable H4895 with 500 grain projectiles out of a 24 inch barrel according to Hodgdon data. If you chop the barrel down to 22" or worse still 20", don't have a compressed load at say 2 grains below maximum then you're looking at about 2000 fps. The first shot out of a cold barrel I've measured to be 100 fps less than the normal velocity of a .45, which brings it under 2000 fps. That's right on the borderline of effectiveness on a buffalo. That's why I stipulated 2200 fps in a 22" barrel with a 500 grain projectile as minimum with the above powders. The .450 Howell should do that.
