Wildcatter264,
A flat nosed bullet in 458 caliber doesn’t need to expand to kill deer at 250 yards. I use cast in my 458wm at 1750-1950 fps and it kills just fine. Sir Bob has a lot of 45-70 loads he can share using a Ruger #1 and jacketed bullets.

http://www.bigbores.ca/

Best regards,
F01