When my .416 Rigby has a scope, it's in detachable Talley rings so the scope can be taken off if I hunt big stuff in thick stuff. When scoped, it's just as flat-shooting and accurate as a .375 H&H.
I must also comment that while the .458 Winchester hits somewhat harder than any of the three .416 "R's" (Rigby, Remington and Ruger) it would take a hell of a lot of buffalo killed to find any statistical difference. If you make a good shot with either, the buffalo will soon be dead. If you don't, you be flinging more lead--or copper.
