Don't listen to me, as I am a Looney here, but I would personally prefer the 6.5 as my primary, call my nuts. Less than the 06 and 280? Sure, on paper, and perhaps in less than ideal situations. I would assume a guide is on hand, that would be my "back-up" and I would pick my shots and lay low my intended game using good bullets thru vitals.
A 6.5 will have a narrower would channel thru game than say a larger 30 cal, yet penetrate they will. A 140 Partition, Accubond or similar, (in a handload or factory that gives +/- 2700 fps will dig deep and I cannot imagine any game animal properly hit, survive. Just me.
The adage use enough gun definitely applies, especially on African game, but to my thinking, proper bullets with proper shooting skills is what gets bullets to and thru vitals. That is the bulk of the task at hand IMHO. Now on dangerous game, quick stopping power by bullets of high caliber, mass, energy may be much preferred.
In the end, Confidence shores up shooting skill, proper bullets thru vitals usually takes care of the rest. Use what you have confidence in. Nothing wrong with a 9.3 or 338/06, some would even choose a 338 Win Mag or 375 H/H but my shooting would suffer as recoil goes up. Others, vary.
Best of success on the trip and safe hunting
Enjoy!!
