Classic regulator spring pack assembly arrived today. Classic problems resolved. Gold spring starts shooting around 200 fps, the red spring starts shooting around 250 fps, and I can tune velocity from 200 to over 300 fps. It no longer jumps from 265-ish to 330-ish.
For reference, here are the old and new Classic spring pack assemblies - old is left/bottom, new is right/top. Sorry for the poor picture orientations. Also, I should have flipped the new one 180 degrees in all of the pictures, so the common end between the two were oriented the same.
As for the X-Valve, I believe the reason I can't get the red spring to start shooting at 250 fps is because I'm getting some pretty bad first shot drop off. If the velocity with the gold spring (using the simulated rapid fire technique) is set at 265-280 fps, my first shot (without using rapid fire technique) varies quite a between two "groups". Sometimes it's 240-255 fps. Other times it's 205-220 fps. I think the former would be acceptable given the recharge rate, dump chamber cooling, etc. However, the latter seems excessive.
Apply these same spreads to the red spring, and I think it would explain why it won't start shooting around 250 fps. As previously posted, I've changed all o-rings, cleaned and lubed multiple times, and played with the torque on the field strip screw (wrench tight seems to be best).
I'm going to try swapping on/offs when time permits to see if the problem follows the on/off or stays with the valve. Any other ideas?
Thanks,
Nathan