First thing today, I built a shelf that fits over my cronograph screens to shield the sun off the snow. Worked!!!
Set up and fired 15 rounds over the screens with 129gr Hornadys and 52.0 grs RL-19. Group under 3/4" @ 100yds. Where it was befor. Load is 1/2 gr under max but think I have more room with the throat I have. Extreame spred was 18.5fps and ave vel was 2952fps.
Moved on to the 140gr Hornady with RL-19. Started at 50.0 grs and went up to 51.5 grs in 1/2gr increments. Up to 51.0 grs was nothing. then at 51.5 grs I got a three shot group at 7/8". As I recall when I first got this thing, the faster I drove the bulets the better it shot. Unfortunately at just over 3100fps with the 140gr bullet case life was 2, as in two rounds and throw the case away. Accuracy was very good.
For this 51.5gr, RL-19 load only three shots, ave vel 2829fps, es 23.1fps. I'm pretty sure I can hit over 2900fps but will find out later I guess. If I can get the accuracy down around 3/4" at 2900fps that might suit me.