KJ Works USP Tactical Mag problem

[ajdale]

So I just bought this gun almost a week ago now, and lo and behold theres a problem.

I bought a brand new KJ Works USP Tactical 9mmx19, and not having heard great things based on old forum posts form 2-3 years ago, I figured, hey they must have improved thier USP series by now, and for the most part it seems like they have.

Untill recently after cycling about 5 fills through the magazine, it seems that it's leaking very heavily out of the the gold valve at the back of the magazine.

No use filling the magazine because all the gas instantly drains out of this valve.

I've tried wiggling the valve around and that's pretty much all I can do, I would disassemble the magazine, but I can't figure out how to pop the rivets holding the gas chamber out.

Anyone have any ideas?

[ajdale]

Bump in hopes of finding a solution so I dont have to buy a new mag.

[LUTNIT]

I had almost the exact problem with my KJW M9 mag, popped the metal shaft holding the BB lips on and looked down and there was a piece of ratty oil soaked thick fiber wax paper jammed in the gold valve. Just pressed the valve in to release the paper and took it out with some fine tweezers, no idea where that paper came from, maybe from inside the gas chamber itself. Dont know if your problem is the same but figured it might help.

[ajdale]

Nothing seems visibly wedged into the valve, from the outside.

Any idea on how to disassemble the gas chamber to take a closer look?

[CDN_Stalker]

With an empty mag, put a few drops of silicon oil in around the 'gold button' and some inside where the gas comes out, press and release a few dozen times to work the oil in. That should help if not fix it outright.

Also, never allow the mags to sit without gas in them, leaks will result.

[ajdale]

That is interesting, I didn't know that leaving the mag empty would cause leaks. If a leak did happen, would it be fixible the way you suggest?

[CDN_Stalker]

Possible, I've fixed a few mags by oiling and working it in. Guess it's the pressure that keeps the seals sealed instead of letting them be in the shape they sit in. Be the mags full or partially, as long as yo uhave some gas in you are ok. I got a brand new G19 mag a while back, it leaked out of the box, did what I suggested, leak went away. Left a KJW M700 mag without gas for about 4 days, completely empty, when I got more propane, I filled it and it gas sprayed out all the cracks in teh backside (where the back end meets the body.) Had to open up, apply gasket sealer, let it sit over ngiht, no problems since.

[ajdale]

I'm not sure how to open the gas portion of the magazine, near the bottom above the magazine there are two hollow pins that go from one side to the other, and I'm not sure how to get them out. I tried to push them out to no avail. The manual from KJW doesn't go into any detail about disassembling any part of the gun so it's no help at all.

Applying lubricant to the valve didn't seem to do anything. Looks like I'm going to have to disassemble the magazine's gas chamber to fix the leak.
Problem being what I said above, I dont know how to remove the pins holding it in.

[CDN_Stalker]

Most likely need to use a punch and small hammer to tap the pins out. I'd suggest try getting more oil (the hole on the top the gas comes out, get some oil in there, that leads right to the O-ring on the release valve) and try working it in again. You shouldn't NEED to open the mag up at all, since it's brand new.

[ajdale]

I agree, but applying a generous helping of lubricant did nothing.