You plenum looks about right for 30 FPE.... If you can't get to the plateau on the curve, then you are just a bit shy on hammer strike, but since you need to back down from the plateau onto the knee to get the efficiency up it doesn't matter.... If I misunderstood and you are up on the plateau, then backing the preload down a bit will give you more shots, but with a slight loss in velocity of course.... Being happy with your tune is all that really matters....Bob
That shot string appears to be unregulated... There is no "knee" in an unregulated string, it is a bell-curve.... The knee I am referring to is explained in the first post of this thread.... You can only find it at a constant pressure (ie regulated or tethered)....Bob