Practice shooting off sticks! Too often, the first time people try it is when they're in front of their first animal on their first safari. MUCH more important than what caliber yuo use.
This is probably the best advice on the whole thread. And to add to that statement, practice offhand also.
I hunted nilgai last weekend. I took one shot on the bench to check zero, dry fired on the sticks a couple of times, and then took a shot offhand at 100 yards. The guide told me in 30 years of hunting he never had a client shoot at the target offhand. He was even more amazed I hit it.
Everybody has their favorite rifle for hunting plains game. I prefer my 375 H&H for PG because all my hunts were in dangerous game areas and it is nice to have a legal caliber if I need it. However any 7 by 57, 270, 308, 30-06 338 and on and on will work fine, especially with premium bullets.
