PP750 Artemis Air escaping from the barrel

[Hemn]

Hello, this is Hemn from Kurdistan -Iraq

I have my friends PP750 with me for fixing air leaking from the fil station, after repair the issue, now i faced another issue when i refill the gun with desired pressure, and after the first dry fire, with the 2nd dry fire all the air will escape from the barrel immediately and the pressure will be zero, means all air will be gone with the 2nd shot ...

i am thinking of one point, please correct me if i m mistaken, this is for sure that the reason is due to the air valve that not going back to its position and the valve will stay open then the air will escape, this maybe because of the hammer that might be dry not lubricated enough!

please any idea, any advice would be highly appreciated ...

thanks in advance
Hemn M
Kurdistan-iraq

 

[thane]

Sounds like a cracked poppet, the valve's stem pushes open the poppet, it reseals with air pressure in a brass seat.
Disassemble and take a look.

 

[Hemn]

Thane, thanks a lot for the reply,

I already disassembled it and checked, there is no damage or obvious spot, all perfect, the brass seat is sitting and fitting perfectly, however what makes me surprise is why first shot is ok, then 2nd shot all the air goes out, why the air valve won't go back to its place and stay opened till all the air escapes!
i have some idea like to put some grease on the hammer as it is very dry not lubricated, moreover i will try to polish the air valve to get a smooth surface ..
any other advice would be highly appreciated

 

[lher209]

Maybe a bad poppet return spring?

 

[Hateful McNasty]

Is the air pressure correct? Like after low pressure point it just will dump to degass?