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KWC Mini Uzi Upgrade


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I want to upgrade my CO2 Mini Uzi to use gas, but right now my Uzi wont even empty half the magazine on CO2. But Red Wolf stock a customized Mini Uzi with a reinforced piston head, that they say can empty a whole mag on full auto with red gas... so are there any after-market parts available any where that I can fit myself? Hopefully just the piston head is all that needs upgrading.


I'd appreciate any help or feedback,



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Murph: All GBB:s have pistons to provide the action. Your nonsense picture post just slows this forum down, thank you.


Firebrand: I'd check for any similar parts that could be substituted. Who knows, maybe a piston head from a Hi-Capa or KSC Glock would make a perfect fit? Also hardware stores that sell plastic and rubber seals might be worth checking out.



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Murph: All GBB:s have pistons to provide the action. Your nonsense picture post just slows this forum down, thank you.


Firebrand: I'd check for any similar parts that could be substituted. Who knows, maybe a piston head from a Hi-Capa or KSC Glock would make a perfect fit? Also hardware stores that sell plastic and rubber seals might be worth checking out.





Hmm... Looking over the parts listing for the KWC Uzi... I see nothing about a "piston" anywhere. So eat me.

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Calm down Murph. GBBs do indeed have pistons. They aren't quite like AEG pistons as they are fixed to the slide and run inside the blowback chamber. When gas enters the blowback chamber, it forces back the piston inside which in turn pushes back the slide.


Some manuals call them pistons, some call them rams (or Air-Rams), and some probably make up their own name. They're still pistons though and there's little reason to get in to an argument over the name of a part.






Now to get this gun to run on Red Gas, you need a replacement base-cap for the magazines...




You also need to remove all of the CO2 gubbins from the inside of the magazine.


I haven't heard of this requiring any type of internal blowback upgrade - far as I know you just modify the mag. However, if there is a blowback upgrade that improves gas efficiency, it can only be a good thing.

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The cylinder is what sits on top of the piston.


In the manual, KWC does indeed call the piston-head/seal (Part P20) a "cylinder" but that is just a bad translation. The cylinder is the rear part of what they call the "nozzle" (Part P08).

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Like in my previous post...


This PISTON HEAD sits on top of the piston, which resides inside the cylinder.. which part don't you understand, Murph?


Anyway, I've made some enquiries and I expect an answer soon.



I dunno, the part where you're a flamer? I'm just going by what I read... Incase you don't know how. I've been on this board since you were in diapers... Just drop it. k?

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Murph, you already made a fool out of yourself. Why don't you just shut up.


Correcting your grammar or terminology according to the mistakes of far east airsoft manufacturers is a definite no-no. Or do you spell steel "stell" because of what Guarder calls their AK conversion kits?



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The Hi Capa Piston head looks to have right kind of proportions, does anyone know how big the piston head is for the Marui Hi capa?


I made a rough measurement of the Uzi piston head with a rule, I don't have a pair of calipers, and I got a diameter of 15.0mm, and 3.0mm for the 'ole in t' middle.


The nozzle recoil pin spring, in the nozzle location assembly, serves to move the nozzle out of the way on the backward "recoil" stroke of the gun cycle, so the next BB can move into place. At this stage in the cycle though the gas valve will already be shut, when the cylinder block strikes the hammer catcher. Or at least thats my understanding, so I don't think altering this would make any difference, at least not to gas consumption anyway. But I know where your coming from.

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It just so happened that I have a PGC Hi-Capa piston head in front of me, but I'm at my GF so I don't have a caliper either. :P


A rough measure of the aluminum part is 14mm, and the thick O-ring should increase it a little. If it's not enough, you can shim it with teflon tape in the groove before putting the O-ring on. The hole looks like 3 to 3,5 mm to me.



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Cheers for the inf, Sale... that part sounds like it might be just the job.


Dentrinity and UN Company stock the replacement piston heads, but only UN Company stock both the heads and the conversion kit. And as far as I can tell Red Wolf don't have the P' Heads. The green/red gas kit is out of stock at the mo, but as soon as it's back in I'll make an order.



SD Piston Head - Dentrinity

SD Piston Head - UN Company

PGC Piston Head - UN Company

CO2 Magazine Adapter - UN Company


Are those CO2 kits hard to fit with out the proper tool?

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Good news friends!... IT WORKS!!!


I went ahead and ordered the shooters design, reinforced hi-capa piston head last week, it arrived this morning(along with an extra £20 charge courtesy of HM's Customs, bastards) and took me about 5 mins to fit. The piston head needs abit of modification to make the O ring fit tightly into the cylinder/nozzle, I used abit of insulation tape cut to thickness, wrapped twice into the piston head groove, like Sale suggested(wtf is teflon tape anyway?). And now it kicks like a mother! I *beep* you not, if you have an Uzi you have to try this mod ASAP!!!


Before the upgrade I could only fire about 10 - 15 rounds in full auto, before the last bit of gas would trickle out like a wet fart. I'd even struggle to empty a mag in single shot mode.


Now I can easily fire a whole mag on full auto, 40 rounds! There is of course abit of cool down, by the last 5 - 10 rounds theres a change in ROF and kick isn't quite as hard. I was then able to reload the gun and fire a further 15 rounds full auto. Theres no change in power, and it might be my imagination 'cus I haven't fired this thing in a while, but IMO it kicks even harder now!


This is the way an Uzi should be!!!... looking forward to trying it on green gas now!



If any1s still interested I'll post a step-by-step guide with pics.

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KWC Mini Uzi Ultimate Upgrade Guide


As many of you know, the KWC Mini Uzi suffers from very poor gas economy, a single CO2 powerlet is only good for about 15 shots in full auto, or about 35 shots in semi auto mode(depending on how rapidly you fire).This guide will show you how to greatly increase the efficiency of the Mini Uzi, and enable you to empty an entire magazine in full auto with gas left over, with out sacrificing power or ROF.

You will need to purchase the Shooters Design, Reinforced piston head for the Mauri Hi Capa 5.1. It is available at UN Company and Dentrinity priced US$16.00 or about £9.00.


Step - 1
Take off the upper frame/slide by pressing the slide catcher back and lifting the slide.

Step - 2
Carefully remove the cylinder base, hammer, recoil springs and bars by pushing the cylinder block back slightly, then lifting everything out at the same time.

Step - 3
Place the hammer, recoil springs and bars to 1 side. Turn the cylinder block upside down so you can see the cylinder/nozzle.

Step - 4
With a small cross head screw driver, remove the 2 screws that retain the nozzle location assembly. Now remove it, taking care not to lose the screw/pin and place it to 1 side.

Step - 5
The nozzle location assembly needs no modification.

Step - 6
With a long cross head screw driver, remove the original piston head from the piston. Keep the retaining screw but place the old piston head to 1 side.

Step - 7
Keep the original screw as you will be needing it later to attach the new piston head.
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Step 8


For the next step you will need a roll of electrical insulation tape/teflon tape or the closest thing. Cut off a length about 10cm long.


Step 9


Now cut 1 strip approx 3-4mm in width from the entire length of tape, so you are left with 2 strips 1 thicker than the other, throw away the thick strip.


Step 10


Before placing the O ring onto the new Shooters Design piston head, wrap the strip of tape you just made, tightly around the groove in the piston head. Now you can place 1 of the 2 O rings(1 is a spare) onto the piston head so it sits in the groove.


Step 11


If you can get hold of some silicone grease, rub a thin coat onto the circumference of the piston head before mounting it.


Step 12


Again using a long cross head screw driver, with the original screw you removed earlier, attach the piston head to the piston.


Step 13

Now replace the cylinder/nozzle back over the piston head, there shouldn't be any resistance doing so. Screw the nozzle location assembly back into position. Mate the cylinder base with the hammer, springs and guides and slide it back into the gun casing. Replace the upper frame. Now you are ready to load and fire the gun as normal.


Happy shooting!




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