RUN AWAY GUN! - kwc.

[jaymz1911]

Hi... I just bought this KWC-Mini UZI. And I finilly got around to test it out. First off, 1 mag is propain, filled it up and no leaks, put some ammo to it... Put the mag in the gun, cocked it, selecked semi. Shoots fine. Put it on full auto, gets half way throught the mag and dumps the rest of the gas. So... I try this again and refilled the mag with gas and bbs. Set it on full auto. ok starts to fire and let go of the trigger and the gun keeps firing... hummm I thought to myself... this isn't vary safe... So I tryed the co2 mag and it did the samething.... :???:

Any ideas?

Thanks

[Danke]

If you cycle it with an empty mag can you tell if the sear is engaging?

Could be the bolt is loose and not catching or that the sear or where it engages the bolt is worn.

Last Q, was this outside? I think it's been too cold here lately for gas.

[Drake]

It's a typical thing for stock KWC Mini UZIs, their piston heads are a joke and gas usage is horrendous. It'll be made even worse if you're shooting in cool weather. What's happening is gas is being used up very quickly and cools off the mag/co2 cartridge, and pressure drops rapidly until it either isn't sufficient to close the valve (in which case the gas gets dumped) or you get a partial cycle (so the bolt goes back part way, but not enough to engage anything, the heavy recoil spring in that thing slams it back shut, it hits the valve while the sear is still disengaged, so it pops back again, and repeats that way until the gas is enpended and/or the pressure drops too much and the remaining gas gets vented).

If you can fire off an entire mag on semi and everything is fine, it's not the gun.

The solution is performing the piston head swap; you simply need a Shooters Design piston head (or similar -- avoid the ones with a ported face, it won't work well here since the diameter of the piston is slightly too small. Thats why you need the teflon tape to sit under the O-ring and increase its diameter a tiny bit) and some PTFE teflon thread seal tape, and basic tools (screw drivers). You can probably still find how to do it online, it's a pretty simple operation.

The new piston head (which actually seals) improves gas usage noticeably. I went from not being able to empty a mag on auto to getting about 1.5 mags off with quick bursts.

[jaymz1911]

Originally Posted by Danke

If you cycle it with an empty mag can you tell if the sear is engaging?

Could be the bolt is loose and not catching or that the sear or where it engages the bolt is worn.

Last Q, was this outside? I think it's been too cold here lately for gas.

Heya Dan. Nope ... I fired this indoors, but I might go with what Drake said. Plus I'll take it apart to see if anything is broken.

Thanks for the help

[Drake]

I wasn't very clear in my original post, specifically the piston head you want is the Hi-Capa one.