Ive wanted to try some 1680 in mine but cant find it anywhere.
Ive tried, H110, Lil Gun, and A2200 (if I remember correctly). Lil Gun at around 9.2gr with a Rem 7-1/2 and 20gr vmax has given me the best results. My last groups with hovered in the low .4s for 3 shots. My velocities seems pretty erratic though with this powder.
My velocities are much more consistent with a2200, but the accuracy isnt quite as good, but as a disclaimer I will say Ive not worked up alot of loads with it.
Scooter