I haven't shot lot of .243 factory loads, but most has been the blue box Federal stuff in 100 grain, and it has always been more than acceptably accurate. I mostly handload 100 grain Sierra's in both flatbase and boattail. Recently loaded and shot some 80 grain Sierra's boattail that were superbly accurate. My grandson killed his first deer with one of these last year at 187 yards bang/flop/dead. Sierra used to offer their Premium ammo line loaded with Sierra's bullets, and may still. If you could lay hands on some of that I'd bet on very good accuracy. But again, you never know what a particular rifle will "like" till you try it.