I loaded 30 rounds, in the 17 twist 308 today and shot for groups. 50.5 grains of H4895, *compressed load. (do not use in a fast twist rifle)(start lower)
It was about 8 degrees, velocity varied quite abit from 3360-3438. not sure if it was the crono as it is stored outside in the shooting house where it is also 8 degrees.
First I shot a 7 round group that put 6 into sub 1/2" at 100 yards. Scott shot another 5 shot sub 1/2", and I shot a third that was sub 3/4".
5 rounds at 400 showed about 2" of verticle, 4 moa up, but the wind played hell with them.
600 yards with 12 moa elevation put me on the steel gong sporatically.
I put this rifle together for fun shooting and it is a gas, the mini muscle brake adds a bit to that fun, seeing the snow fly with the sighter shots at 600 yards helped with my come-ups.