KWA CZ 75 system 7 venting all the gas in a single trigger pull.

[k.a]

My KWA CZ 75 is venting all the gas in a single trigger pull, I heard that the piston head perishes on KSC/KWA guns, could that be the reason or I am braking up the wrong tree . Thanks in advance.

 

[Sneaky]

Could be the piston.

How well maintained is it?

More information is needed really, also a video of the issue.

 

[k.a]

Thanks for the reply mate, going by how GBB's work that was my hunch and yes replacing the piston has stopped it venting but now it double feeds and dry fires when the gas is low and the bb's just accumulate in the chamber and barrel, sometimes slide locking back when it gets to the last round.