H4831SC, 140gr SST, CCI BR2 primers, Lake City prepped, fireformed/neck sized brass, OAL to fit the mag.
Start at 53gr and work up from there. Mine was around 56/57gr depending on powder lot.
Since throats and chambers can vary, always start way lower then needed just to make sure. I always find that H4831SC works best on the high end of load development. Just be careful and approach in 1/2gr increments.
If you can shoot over a chrony, expect to reach 2950/3000fps as an operational max in 22/24" barrels. Odds are pressure signs will start to show around that velocity and accuracy will go for a dump after that point.
Jerry