Try this method instead:
1. Make sure there are no more paintballs in the gun.
2. Slowly start to unscrew the tank.
3. As soon as co2 starts to leak out, keep pulling the trigger on the gun while continuing to twist the tank off.
4. When the gun is no longer able to fire, just take the tank off.
With the way you were doing it, you're letting co2 escape and the pressure left in the line is killing your orings.
As for the hexagonal looking thing, that is your burst disk. Do not fiddle around with it! That's a safety device if you're tank is overfilled or the pressure just increases due to heat. Instead of the tank blowing up, the excess co2 will vent out of that piece.
Silent in Error
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