Oh well. Depending in the "working pressure" capable of 2,000fps with 400gr. or 2,100fps with 350's.
Brian Pierce got complete penetration on both shoulders on a cape buffalo with a factory 400gr. Solid at 1,900fps, so it would work if capable of lever action loads.
My '86 just loves Bullet Barn V/hard cast 450gr. FN's at 1,850fps. I didn't bother going faster besides, we're fresh out of cape buff about these parts.