I had a chipped sear recently which gave these exact results. Very frustrating to diagnose because it's typically not the first place you'd look. Take
I found the same thing in my reading on Mac brown, the oring was out of order.
That's the way I got the gun.
If your pic shows the order of how you had it assembled, the power tube oring should go behind the little spring.
Newer Level 7 valves