I just bought some 420 Raptors for a .450 Rigby heading my way. I was speaking to a friend and he voiced his displeasure at shooting anything under 500 grains in any .458. I assured him I would be just fine. . . and the buffalo will not be fine.Have you tried the 420gr Raptors and 450gr solids? Those 420s are also devastating on buffalo and would penetrate from any angle without having to be so careful.