KSC Glock 17 Issues

[pizzainthemorning]

Set up:
KSC Glock 17, pretty much new, stock on propane, summer weather and mags filled upside down properly.

Problems:
Sometimes the gun will go full auto, shooting in bursts of 2-3. After each burst the slide must be manually cycled.

Sometimes the slide will cycle only partway and gas will leak out of the mag down the barrel. This leak happens sometimes when the slide is all the way forward also. When the slide is cycled manually the leak stops until the next shot.

Sometimes the gun fires 1 shot only, after which it must by cycled manually.

Observations/Comments:
The gun is lubed up the poop shoot. I've heard you need to lube 78 and other parts especially. Well they are. Wiping off lube and trying to shoot dry doesn't help either.

Sometimes the gun works just fine, though this usually happens when either dry firing, or when there is about half a mag of gas left.
The rocket valve, and as far as I can tell all other internal/external parts are in very good and seemingly working condition.

THE ONLY THING I can spot is that the blowback chamber is stiff. Despite the amount of lube, there is friction somewhere (I'm pretty sure with the chamber (22) and the rubber seal/o-ring (27)). On other GBB's I've dealt with, when this chamber is pushed forward and released it snaps back no problem. The Glock snaps back, but there's a small 0.5/1 cm gap that is left before part 22 goes all the way back. It can be pushed back fully without difficulty but it does not go back on it's own. I can't verify this on firing of course, only during disassembly. One of the part 23 springs is slightly (I really, really emphasize slightly) "crumpled" near one end.



I don't know. Help?

Thanks,
Alex