[rustysniper]

With the upper off...

If you cock the hammer, does it:
- trip the knocker back YES
- stay cocked YES

When you trip the hammer, does it:
- knock the knocker out YES

Then when you cock it back, does it do what it did in the first step? If yes...your lower is fine (at least so far).

With the upper on, it's knocking the mag and the gas is venting into the nozzle.

- is the bolt going back at all? If not, your float valve might not be closing...does it move freely NO
- no issue with manually racking the bolt? guessing not NO
- try adjusting it so that the float valve is as far back as possible (in reference to the front of the nozzle?)
- check all your o-rings (looks good)
- take a good close up pic of your nozzle, valve, spacer, rod and post it will do

Question....could I have screwed up the positioning of the selector in the receiver that would affect it?
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