Just ran some solvent through, cleaned it up really well and removed some black nasty gunk.Piston was falling at a slow rate, so may be this whole kanundrum is coming to a close! I think when I first cleaned it up I did make the mistake of putting grease into the gas cylinder and piston area...lesson learned its bone dry now so well see where it goes.
I actually re inspected the gas system, and there still seems to be an issue.
The piston, without the gas plug in will slide back and forth freely in the gas cylinder, passing the "tilt test" in a way however the piston will never come out the back of the cylinder and fall towards the end of the gun. It essentially stops at the point that is in the first picture linked here. Upon inspection of the cylinder there appears to be like a little circular piece of metal that surrounds the interior of the cylinder that is stopping it from moving back but im not sure..
When I put the gas plug in and tighten it all the way down, the cylinder pushes out but will not move at all and is fit in extremely tight like can be seen in the second image. I can loosen the plug so the piston is flush with the opening however the piston will still not move at all and requires to be punched out via hammer and punch.
So...any ideas??
Pics
http://imgur.com/a/gKceJ
In the first picture it looks like the piston isn't aligned with the cutout at the bottom of the cylinder. When you put the piston in you may have to drop it down a few times to get the alignment right, but it should fall through that hole BEFORE you ever put the gas plug on. If you were to tighten the gas plug down on the cylinder as it's shown in the first pic you'll force the piston through at an angle and bind it up tight, possibly damaging it or the cylinder in the process.
Seriously, watch this entire video before proceeding further: https://www.youtube.com/watch?v=MzPw9BD56hU
As pop said the piston must be aligned correctly before the gas plug is tightend down . You can take the eraser part of a pencil and turn the piston while its in the cylinder to align it.
On one of mine I had to file the flat section area at the end of the cylinder to remove a tiny bit of material to get my piston to pass the tilt test. The required tight fit of the piston comes from the other end of the piston not the tail .In the pic your cylinder in that area looks a little chewed up .
Dnas, no offence, but did i read that right: you took a hammer and punch to the piston to knock it out?
I'm not sure what the piston is made out of, but I think the metal might be a little soft to use a punch on it. Same for screwing on the gas plug tightly before the stem of the piston is properly sliding through the back if the hole in the cylinder.
Are you sure that you haven't deformed the piston at all?
Can you post a picture of the piston and a view of the gas cylinder by itself from the front and back showing the holes for the piston and its stem?
The piston is fine, its the cylinder that appears to be too small to fit the piston
Visiting Chalkriver, Yomomma, or Tactical teacher would be a big help for your location if you can't solve it yourself through the forums.I'm just gonna summarize this since I feel the combination of my noobness and bad luck in acquiring this lemon is starting to irritate some, but basically great gunsmith guy fixed up that gas chamber and piston and now its correctly passing that tilt test. Live fire test to follow... fingers freaking crossed.




























