280 rem
I went outside the typical box
.5110" (4) shot group with 160 grain accubonds at 100 yards
56 grains IMR 7828 ssc ( slower burn ) 1-1.5 gr under max pending on manual
2700-2750 FPS
2'' high at 100 Yards
zero at 200 Yards
hold dead on anything out to 250 yards
2nd mildot on scope and I am nuts on to 300 yards , zero hold.
Good luck , I've tried a bunch , this worked best in my browning Abolt II .280