I dont have a ton of time to write this but I did do some testing this after noon.
I loaded the following at 2.845 OAL (shorter than recommended to insure bullets did not deform after hitting mag under recoil. Was given the "good to go" by the manufacturer when asking if it was advisable)
Retumbo, Lapua Brass, 215m primer, 2.714 trim length
94 gr, 94.5 gr, 95 gr, 95.5 gr, 96 gr, 96.5 gr, 97 gr, 97.5 gr, and 98 gr
At 97.5 I experience a bit of crunch when seating the bullet and a bit more at 98 but nothing too bad.
After shooting the first 8 (3 shots each) loads I was seeing sub moa groups but nothing that was outstanding. My standard 300 grain otm produces 1/4 moa on typical days.
Then it happened, I got to the 98 grain load. I picked a new blank target dot on my cardboard at 200 yards, and let the three go.
The center to center was 3/8 at that distance giving a 3/16 moa result.
After getting these results i shot a few more, indicating my results were not a fluke. Three of these additional shots were on mild steel, leaving less damage than my otm's - thought it would be worse seeing that they are solid copper.
Next, 245 grain lehigh bullets.