Will just add that one of my good friends used the 100-yard zero on his one safari, on a ranch in Namibia where both Ingwe and I have hunted. He was using a .30-06 with, as I recall, 180 Partitions--but one of his opportunities was at 300 yards. This can happen even in flat thornveld, and because he assumed no shot would even be as long as 200 yards, had no idea where to hold. (And neither did his PH, because believe it or not, many PH's are not all that sophisticated about rifles.)
Everything turned out all right, but I would advise whatever sight-in distance you're used to here. Which means not assuming anythingabout the distances you might shoot, or anything else. It is YOUR hunt, not anybody else's--including the PH. Have run into a number of PH's who assume they can "judge" the range better than a laser rangefinder.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
