I don’t have a 243 so keep that in mind but I do have a 6mm creedmoor with a 7 twist. In my rifle 105 Berger hybrids in front of H4350 is the bees knees. The 105 hybrid would be where I started. I use a whole lot of Hornady bullets but I’ll say that I’ve never once had a rifle that wouldn’t shoot Bergers into tighter groups after proper load workup.
