Gas pistols jamming (or something)

[MrMoo]

Hey folks,

I have two gas pistols, a green gas KWA CZ-75, and a Cybergun CO2 FN Five-Seven. Both guns have the same problem.

Intermittently, when the slide is locked back and I insert a new magazine, I hit the slide release to drop the slide back down, and it gets stuck half way, causing the magazine to eject all of its gas.

It wasn't happening much when I was testing out both guns and trying to shoot targets, but, I took them out for a game today, and both guns were consistently getting the same problem.

I don't really know anything about gun maintenance, so, any suggestions would be appreciated!

[Hectic]

clean and lube the parts, u really can wash em with warm soapy water then dry em with some.duster or compressed air then lube the slide rails and the trigge/hammer/valve knocker area with soke super lube or silicone grease

[lurkingknight]

watch out you don't over oil the kwa. the hopup rubber sucks up oil and swells, causing misfeeds.

[MrMoo]

Thanks guys, I'll pull them apart and clean them out.

[Hectic]

i wouldnt use any oil on the guns at all (aside from in gas) all ull wanna do is have a thin layer of super lube/silicone grease on the contact poins. slide rails, trigger to hammer to valve knocker, the lil rails of the blow back unit and thats prey much it every cpl of games, or any time u get it wet, sandy, muddy ect.. just clean and relube

[MrMoo]

Okay, I looked up some "how to" videos, and I've managed to dismantle and clean my CZ-75. Surprisingly pretty easy! Anyway, I gave it a good cleaning and a small amount of oil. I didn't see anything that looked particularly dirty, broken, or otherwise out of place. After I put the gun back together, though, I'm still having the same problem.

Any other ideas?

[beta678]

Weak recoil spring? Maybe try racking the slide instead of using the slide release and see if that helps?

[MrMoo]

Doesn't seem to be the spring, but, I'm not an expert. If I rack the slide and let it drop back (with no magazine in it), it never seems to get stuck. Maybe that's a clue? Here are some images to try and explain:

Gun sitting normally:



Gun fires to a lockback, or I manually pull and lock the slide back:



Hit the slide release, slide drops back down, gets stuck part way (only seems to happen when there is a magazine in):

[Hectic]

not sure how the recoil spring will have anything to do with the gas venting.
somehow the valve knocker is hitting the valve, thats the only way to vent the gas. Seems a lil odd (tho im not all that familiar with the CZ pistol so not quite sure what the internals look like but there has to be some sort of disconnect that moves the knocker back when the slide is racked. So either that part is worn/broken causing the knocker to either stay forward or get pushed forward when the slide moves.
i had a simaler issue with a glock before, the lil loop that connects the knocker to tue hammer was brokes. Gun would shoot fine sometimes, sometimes would vent on mag insertion and sometimes vent on slade returning to battery.
id have a gun dock lool at it personally