In my experience, any big bore shot seated at a bench will really hurt. Best to shoot offhand, from a standing rest or from the sticks. Rifle fit is of critical importance with a big bore.
My .470 is quite tolerable offhand for 10 to 12 rounds. More than that and I have a headache later in the day.
The two rifles I usually bring to Africa are a .416 Rigby and a .470 N.E. Neither is punishing regarding recoil. And I practice a lot with them in the months preceding the safari.
Most unpleasant rifle was an issue 1903A3 Springfield. The stock design was very poor for me and the rifle didn't fit me at all. Shooting it from the bench just plain hurt.
