In my original post I forget what powder I said, but I meant to say Accurate 2520.
Here are some .45-90 loads at 43,500 psi:
.458 Hornady 300 HP, 74.66 grains of Accurate 2495, 2600 fps
Barnes 400 FNSP, 60.09 gr of accurate 2495, 2167 fps
And for the penetration junkies:
450 Barnes Banded Solid, 52.92 gr of BL-C2, 1884 fps
The numbers above show that the .45-90 can only match the .458 Win with a 300 grain so for those that have no use for 300 grain bullets it is not a valid comparison.
BTW the empty case capacity I am using is 88 grains of water for .45-90
