Well, after harvesting 30 or more deer with a .243, I don't know what the best is but I can tell you what I used. Never lost a deer with the .243. Never had one run over 75 yards with a heart/lung shot, most only made it around 30-40yds. Good blood trails too. Only had one bullet not exit. I always used the factory 100gr soft-point. A mix of Rem Core-lokt, Fed Hi-Shok, and Win Power-point. Practically all the same. Nothing fancy, just plain-jane 100gr soft points and they have always served me well.