Gretik

Checked the rocket valve just in case, that's functioning. The ruined nozzle return springs will definitely not be helping, but I messed them up when I first tried to fix it!

Will be trying to put this back together on Friday or Saturday, hopefully - if not, then next week. Looks like it might be the sear or the disconnect lever causing the issue.

The KWA online store does, else ask Patrol Base, see if they have them in or can order them in?

Slept now since then, will get spare parts and have a crack at fixing my monstrosity first!

Cheers for the advice, but it is way too late now, it's a few months old, has been a little bit battered in the field and I know that it's missing one small spring (part 82), which I lost. If I'd clocked on that it was faulty in the first week or two, sure - can't be bothered to go through the hassle of trying to prove that it wasn't my fault. (Especially since some of the wear and such most definitely is my fault!) I work in supply, if not directly in retail and I know how fantastically annoyed I would be if someone tried to return this gun after the time I've had it.

Dismantled, can't spot the fault and I'm not about to start filing random parts - will probably sell as a boneyard and move on.

Haven't taken it apart yet, but pushing the magazine up caused it to immediately and catastrophically vent on the first shot!

Hello, My guns are a fun bag of broken at the moment! My KSC G17 is essentially brand new, though it looks battered to all hell externally after a particularly brutal woodland game spent tripping, falling and scraping. The gun has an issue where it fires one or two shots, and then locks up part way on the return to battery - which causes it to gas out. I've tested/cleaned and stripped everything in the slide and bar the fact I now need to replace the nozzle springs due to my own mandhandling, everything there was A-OK. (The nozzle still moves smoothly, but I'm aware both springs are kinked now and should be replaced.) The telling thing is that with an empty magazine, no gas - if I hold down the magazine release and rack the gun with the trigger held - the gun sticks about half way on the return to battery - every time. From what I've been able to tell on various threads and forums, this sounds like a problem with part numbers 81 or 87? http://www.airsoftevents.com/medias/images/G17.jpg Any help would be appreciated, especially if I am wrong - my current thought is that part 66/67 might be putting unwanted pressure on 81?

Ended up needing to trim it slightly, about half a turn in all - brought it down to just below 500fps consistently. Lost a screw for the oversized hand guard, which I need to seriously work on to make secure - but other than that it performed flawlessly!

Cheers for the advice, will leave it cocked for as long as I can - but I'm playing in about 4-5 hours

Tried padding the o-ring groove of the 'new' piston with PTFE, as well as the screw holding the bearing but it still leaked - can't see any scratches on the rim and my second attempt at padding out the o-ring left it unable to even fit into the cylinder, so I'll probably look at getting a new one. Meanwhile, applied PTFE to the hop rubber where it meets the barrel and that has improved the air seal of the barrel enormously. I don't think the cylinder head and the hop up rubber are forming a perfect seal - but it's currently pegging 500 very reliably. I now need to trim the spring slightly to bring it down to more like 480/490 - it is occasionally wandering over the 500 mark. (I now both love and detest PTFE tape, fiddly damn stuff. I thought grub screws were bad...)

Well I swapped the piston for the stock one, and realized quite how bad the seal on the 'new' one was. The O ring on it must just be totally the wrong size. FPS is now 500 with a 150ms spring, I'm going to take off the new brass spring guide and replace it with the stock one as it's a better fit for a 150 spring - then open up the hop and add a bit of PTFE to keep it sealed nice and tight. Will post how it goes The fun and tribulations of setting up a sniper...

It's a generic madbull 6.03 tightbore, could always try it with the stock barrel again if needs be. As for the hop up, it currently has the stock bucking in it as I wasn't confident that the softer blue bucking from the cz kit wasn't getting squished or displaced when I inserted the barrel. (It certainly didn't feel loose.) That said, I may attack it with PTFE tape.

The rim in contact with the cylinder is smooth, there are small dents or pits in the face of the piston head - looks like possibly something was caught in it and dented it when it was fired at some point. Ptretty dumb on my part if that's so, but it shouldn't be affecting the air seal (tested the compression of the cylinder alone and it was fine).

Tomorrow, when I'm a bit less irritable with the whole thing I'll take it apart and try your advice - I tapped it in the first time, but hand fit it the second. Also found that the piston head has some odd pitting on it, but only along the front face of it (along the metallic rim, rather than the rubbery bit) - the sides are still smooth. Cheers, DanG