I believe that for a one off trophy hunter or a casual hunter the minimum calibre should be 338Win Mag using Woodleigh 300gn round nose softs and solids.
Forget this crap about shooting our buff with a 6.5. As far as I am concerned the persons involved were on an ego trip and have done their reputations more harm than good !
-------------------- "Dogs always bark at their master"
Sir Seretse Khama.25th June 1949