OK, i’m Getting consistent groups in my 20” barrel with 135 grain Bergers. I’m only getting 2580 FPS using 41.5 gr of H414. I could press up on grains. Question: would MAGNUM primer change/help.
I'm going to strongly suggest h4350, with the implication that this SHOULD get you safely closer to 2700 fps.I like a Magnum primer with that powder, just because it's a ball powder. It might help, but not enough to warrant a new load work up.
You could try different powders. There are a few that are supposed to give more velocity.