I have hunted Africa extensively with my Dakota 76 in .416 Rigby, using factory loads exclusively. While I prefer my .470 for elephant and DG followups due to it's handling qualities and fast second shot, my .416 Rigby has performed splendidly on everything from Klipspringer to Cape Buffalo.
Sighted in dead on at 100 yards, it is slightly high at 50 yards and 3.5" low at 200 yards.
Based on my personal experience in the field, I see no reason to "hot rod" it. 400 grains at ~ 2,370 fps has proven itself over the course of 100 years of African hunting. Recoil is tolerable and it will kill anything that walks the face of the earth. There is no need to "make it better". If you want .416 Weatherby ballistics, then buy a .416 Weatherby, though for the life of me I can't see why one would be needed.
