G&G raider venting gas

[faggibles123]

I have a g&g cm16 version 2, and 2 version 2 Mags for it.
The mags hold their gas no problem and have no signs of leaking. Sometimes when I put the mag in, some gas will shoot out the barrel. The problem comes when I rack the bolt and then shoot, sometimes I can get maybe 8 shots out of the mag, but other times it seems like the hammer is not coming off the release valve and all the gas starts hissing out.
I am using abbey 144a green gas, and the mags are warm enough. I haven’t received the silicone I ordered for the o ring in the bolt so it could be that. I haven’t found any recent forms regarding this so I created one.
Mant thanks in advance for your replies