When I shot long range matches I used 65.5 grains of H 4831 and for the max velocity
I used 67.5 grains(This is well over a maximum load and should be approached with caution).
The chamber "MUST" have free bore to shoot the 67.5 gr load.
The new H4831sc should work very well but start around 64 grains.
My barrel was 29.6'' and velocity with 65.5 grains of H-4831 was 3140 ft/sec using a rem
9 1/2 m primer.
Standard deviation for load 1 was 8 ft/sec and for the hot load it was 9 ft/sec. I tried the fed 215
and SDs went to high teens(17 to 19). Velocity increased almost 30 ft/sec and accuracy fell off
to 3/4 MOA and occasionally threw fliers.(The primer was to hot for this powder and load.
The hot load(Not recomended because it will sometimes blow the primer) was 3255 ft/sec
with the same primer.
Both loads shot well under 1/4 MOA and the only time I used the hot load was in poor conditions
and the ammo had to be kept cool.