Tatume - I've used the 400gr. SSSP with both .032" and .049" jackets (1970's) and trusted it completely on bear and moose, driven at over 2,000fps from my 2" Amercian. Deep penetration and mostly exits with 2 1/2" to 3" exit holes on moose with the .049's) I would have preferred if Barnes would have kept the .049" jacket, the .032" seem to be OK at 2,150fps initial vel.

My problem with the 300gr.SSSP is it is so short, that any expansion (and that's going to happen quickly) is going to leave very little or no shank left to hold the core. Thus, I didn't use them or even try 'em. I was concerned it was too short to give the penetration I wanted for moose and bear - however, it would be dynamite on deer, perhaps hogs - light stuff. I think you'd want to stay well away from any eating part of the animal.

The original 400gr.SSSP is a wonderfully accurate bullet. All 3 .458's, a pair of 2" and a .458 Alaskan put them into 1/2" to 5/8" groups at 100 meters off the bags, driven from 2,150fps to 2,400fps. The BC is .389 as well, so they're quite flat shooting compared to most .458 projectiles, and with a 3" high 100 yard zero, makes for an easy 300 yard deer, moose or elk bullet. I'd go with 400's.