As the capacity is 97gr. water, compared to the .458's 90gr., the ballistics should be pretty close + a few fps. I haven't pushed this rifle, as my back(and my mind) don't like much recoil these days, however I did load to 65gr. of Reloader#7 with 400gr. Barnes SP's for 2,380fps which was a moderate load. I assume this ctg. will do close to 2,500fps with 400gr.
: A nice soft load for the 520gr. cast bullets, printing with the 400gr. jacketed, was 55gr. Reloader#7 for $1,900fps even. Accuracy with the cast bullets was a 1/2" hle for 3 shots - regularly, with WW bullets and Moly-stick lube. The same load did 1,910fps with 420gr. from an RCBS mould, again, WW metal and Moly stick lube.
: At from 2,100fps to 2,400fps, the 400gr. shot into 1 hole, as well, with 3" vertical dispersion between 2,100fps and 2,400fps.
: The same 55gr. RE#7 puts 400gr. jacketed out at 2,042fps. along with 350 heavy jacketed Speers.
: 350gr. "XFB's" clock a bit more speed than the 400gr. jacketed with .032" jackets.
: My rifle has a Shilen barrel with rather shallow rifling. The fairly soft, oversize WW bullets are responsible for gripping this rifling, contrary to popular belief that they must be hard. Not true.