I have taken African plains game cleanly with a .280, which is nearly identical to a .270 in performance. The .270 is very popular there for plains game and will work well for everything under the size of eland. It would work for eland but they are so large that most people use a larger cartridge. Ammo for all the cartridges you mentioned is available everywhere. Ammo for less popular cartridges like my .280 can be very hard to find in remote areas so stick with the .270 and it will serve you well.