no cocking

[sub202]

I own an FX Wildcat Caliber .22. After I found an increased pressure loss of the rifle, I replaced some O-rings (Regulator was not disassembled).
After assembling the rifle, I tested (pulled the trigger) the gun with pressure at 200 bar and without loading any bullets.
Unfortunately, there is no cocking (pressure relief via the barrel). I also hear the hammer sound.
When the loading lever was pressed again, part of the pressure was released via the Breech Block, which seemed unusual to me.

Any suggestions?