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I never even realised you could do this... might make this the default even at the risk of being banned from forum. Also, the way you stuck the dragon through the thumb hole... looked wrong. 

Made a mistake. That part no.17 that broke which I mistook for a hammer and corrected as being a disconnector is in fact a sear, as in THE main sear for the hammer. So I don't know what's going on whe

Is it odd I'm trying to read the newspaper?

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Ill get one once proven. For the time being my P90 is fine and I expect if anything breaks ill buy an oem spare.


Once theres a steel or proper solid ali hop unit/bolt stop ill consider this too as a a nice drop in.


on my phone, my spelling will suck

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Hi guys,


I've been following the thread but haven't actively participated until now.  


Recently, a part (#22) broke which caused the gun to not shoot at all.  As I live in Hong Kong, I had parts readily available, so I grabbed a steel replacement part from RA-Tech.  Since I was there, I also got myself a steel firing pin / valve knocker (#10), and valve locker (#11).  These parts dropped in quite easily and I got the trigger group back together in short time.  However, currently the problem is that the gun would only fire in automatic regardless of what firing position the selector was in.  


This problem didn't exist previously even when I had a paper shim fitted to the front near the trigger.


Could anybody shed some light on this?



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  • 2 weeks later...

I have one mag leaking from the release valve--other two mags are OK (for now).


I bought these:  http://www.ebay.com/itm/172126151837?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT


Haven't received them so I can't vouch for them.  But this is the O ring that is leaky on mine--part number 134.


The manual is very useful in that it gives the O ring dimensions.  So a web search should give good results.


On a positive note, my new nylon bolt stop has outlived all previous iterations of the part.

Edited by machgo
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I made a little video to help gbbr user to fix their gas leak on P90, I really hope this video will help. Of course it's not the best and not the only one way to fix gas leak, but it's a good one as well. 


I didn't add subtitles yet, it's longest that make the video ;) but I guess see is enough ;)


Edited by Vasriotaep
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Good video!  Not sure I would use a silicone adhesive on the moving valve as you have, but if it works, great!  Did you seal up the base plate also?  I don't recall seeing that in the video.  That seal is prone to leak as well, and violently, as there is only a very thin O ring to seal the rectangular piece.  I used an automotive gasket making material to repair that yesterday.


My P90 suffered a breakdown today that I've never seen before in any gun.  The pin that holds the two halves of the nozzle together as well as the nozzle return spring, broke in half--right in the middle, inside the nozzle--allowing the return spring to come off.  The spring itself was completely fine.  On one side of the nozzle the plastic was slightly cracked and swollen around the hole for the pin.  A little file work was required to allow the nozzle to move smoothly through the track piece.


One good thing I observed was the use of thread locker on the screws in the bolt assembly.

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Nitrile Orings is what you want.


Yeah two of mine are leaking from the release


Cool I'll get some of those eventually thanks


I've fixed all the leaking mags now, added a little bit of sililcon oil and it was still leaking from the release, managed to fix all of them with this weird trick, by sticking a small screwdriver into the release's brass bit and just wiggle it / push in different directions, you hear the gas leak start to increase / decrease, and it hits a sweet spot where leakage stops altogether, it's managed to hold gas for a day and continues to hold it after inserting / releasing the mag. 

Edited by blobface
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I have a niggling issue with one of my mags just like that. If you take it apart the offending o-ring causing that leak needs very tight tolerances to fit. It squeezes between two shafts so too thin and it will leak, too thick and it won't even go in to seat properly and not release any gas at all. It only leaks on me if dry, presumably because it shrinks down a bit, but after oiling it for a bit it seats perfectly again. Haven't tried shimming the inner shaft to effectively widen the o-ring when it's on which is what I usually do when an o-ring is too small because I only need to go over a hair's width for it to be too thick.

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  • 2 weeks later...

I have this wierd issue. At first semi would sometimes not work at first I tought it was a magazine issue but then it started happening more frenquently. Then even full-auto stopped working. When I tried to disassemble I pulled the charging handle back, took off the upper and when I tried to take the bolt out I couldn't. I noticed that the hammer was still in forward position. FPS seemed to be lower than usual at the last chronoing btw.

Now I took out everything and looked over but nothing seems to be broken... so I don't know what's going on. :S


Edit: so I was just pulling back the charging handle and pulling the trigger repedeatly and noticed that about every second time I let the charging handle go forward the hammer will go forward too without me pressing the trigger.

Edited by Zereck
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There are two areas on the release valve that can leak. On the valve itself like Blobface described (oiling it usually does the trick) and around the brass insert the valve sits in. It has an o-ring (very thin one) but 3 out of 4 mags I've opened had that o-ring nicked at the factory by the sharp threads for the brass cap. Only way I've sorted that is with sealant.

Edited by renegadecow
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