The detents are easy to check. All you need to do is look at the breach area where they screw into the body. If any of the screw edge is felt inside the body, then the detents are in too far. Only the ball detent should be protruding into the breach.
As mentioned, the efficiency mod could be your problem. A regular level 10 bolt setup requires about 500 psi or more in the chamber to work at the desired velocity. If you use a shorter barrel, that pressure would be higher. When you reduce the chamber volume, you increase the pressure requirement. I don't know the pressure numbers on these, but I'm betting your chamber pressure is probably up around 650 psi or higher. That would require about 850psi or higher coming into the valve. You are showing 800psi on the gauge, but it could be even lower at 700 or 750psi given the error on these things. The lower the differences between the input and chamber, the less likely you are going to get a good seal at the valve orings. If these orings do not seal, then the bolt sticks forward. Rapid firing makes it worst, because the lower pressure differential reduces the flow rate and further accentuates the problem.
The other thing you might want to look at is the alignment of the valve with the body. Check for rub marks inside the breach area or where the bolt goes through the body washer. Is that washer flush or flat so the bolt spring can't bind or twist on the bolt inside the body?
Except for the Automag in front, its usually the man behind the equipment that counts.