With a flat shooting cartridge like a 243, I'd want it at least 1 1/2 or 2 inches high at 100 yards. To do otherwise wastes it's potential for the occasional long shot. The only rifle I have sighted for 100 yards is my 35 Remington. My 257 Weatherby is set for almost 3 inches high at 100 yards so that it still hits a bit high at 300 yards. That much mid range rise is never going to cost you a deer. It has caused me to miss a couple of coyotes over the years though when I forgot to hold low for the mid range shots.