I hear some guys are running h4831 with the 147's. I would be tempted to try it. Probably a bit slower FPS tho.
We shot 150 or so of factory rounds on video at around 1100 yards. You could see they fell in two distinct subgroups that were 1/4-1/3 moa. The average of all groups was somewhat over .5 Moa. Weighing the cases afterward showed a 4 grain es with two distinct groups of brass less than +/- 1gr. I'm guessing from two different machines. If you have not already done so, weight sort the brass and the bullets