I haven't shot any deer with any of the .243's I've owned, but load deer rounds in that caliber for my grand-kids. I used Barnes TSX 85 grains a couple of years ago and grandson #1 shot a nice doe at 150 yards high in the heart-lung area and the deer was dead when it hit the ground. That's decent performance in my book, especially when I was concerned that it might not expand adequately on that type of shot.
For deer, I now load only Hornady GMX bullets in my .270 Win and .243 Win. Being hollow-point gilding metal bullets, they expand well and we don't have to worry about lead in the deer meat, or in gut piles that eagles or other scavengers might eat.