Actually made it to the outdoor range for a while,

and tried the 7.62x39 subsonics at 50 yards.  Remember these were about 1.5 inch low at 30 yards from the supersonic zero, 
11.7 grains, the three in the red circle

Dropped another 1.5"

11.9 grains

About the same.

I did try a couple at 100 yards, but took a few to figure out elevation, had to aim about 15" above the center, using the crossbar of the target stand as the aiming point, that put it about 2-3 inches below the center  aim point.  This scope doesn't have the stadia lines like I have on a different scope.

So they shoot well, no sign of instability.  I think I'll mostly stop screwing with powders until Hornady publishes some information.