How about the 300 Weatherby.
It has the velocity to handle Namibias long shots without being too hard on bullets.
With 220 gn round noses or 180-200gn Barnes X or Failsafes ,it is good for the biggest of plains game without being excessive for Duikers and other small stuff.
Flat trajectory ,good power and not TOO much recoil.
Ammo shouldnt be too hard to come by in an emergency.
Thats why I bought one. Just gotta get myself over to Africa for my first hunt.