I just loaded the 280 last week for one of my clients, the rifle was a ruger m77 mk2.
There were two loads that shot exceptionally well with the 168 Bergers.
52.0 grains IMR 4831
CCI 200
Win brass
168 Berger
Velocity through chrono 2700
0.5 moa consistantly
51.0 grains IMR 4350
CCI...