Sir Jerry, They will be good for pairing with the 400-gr softs, aye ! Your 500-gr Sledgehammers in the .458 WM+ might penetrate farther, but even the 400-grainer will be elephant-capable. That Doc M at MIB is working hard at it, already has some "terminals" with the new bullet, and lots of results with other bullets to compare:
Here is the gold standard for comparison:
And a couple of inches deeper here:
Incredibly the 325-gr #13 FN is just an inch or two short of the 400-grainer at same impact velocity and, more understandably, no improvement as velocity is increased past a certain point with the 325-grainer:
Exponential increase of resistance as velocity goes up ? A velocity wall dependent on the greater-than-first-order test medium ?
That one inch less with the 325-grainer than with the 400-grainer's penetration is adequate for elephant:
It takes an elephant skull frontal shot plus an elephant body to catch one of those little 325-grain boogers !
6 feet of hippo was enough to stop the 450-gr CEB Safari Solid on one occasion:
So the 400-gr CEB Safari Solid ought to be able to do the work if both the 325-gr and 450-gr CEB brass FNs of same caliber can do it.
Ron aka "Rip" for Riflecrank Internationale Permanente NRA Life Benefactor and Beneficiary .458 Winchester Magnum, Magnanimous in Victory THE WALKING DEAD does so remind me of Democrap voters. Donkeypox.