Don't sell yourself short. John Buhmiller was quite a bit older when he took off to Africa to test his cartridge designs on buff and elephant.
I read articles some years ago about John Buhmiller's trips to Africa, and now that you mention it, he wasn't a spring chicken at the time... I also remember thinking that he was a tad on the small side to be regularly absorbing some of the recoil his rifles generated.
(He also didn't dress anything like Hollywood's idea of a man on safari.)
Mr. niteowl77