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VFC/Zero Hammer Fettling

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Hi all,


Recently ran my Umarex G19X at the weekend. Lovely fun, but only ran at all with the mag it came with, and none of the WE mags I already have. I already changed the routers for curved shape, Guarder air tight ones, and in the house they all work and feel the same. I’m guessing that the cold is exacerbating any tolerance issue in the set up, and the hammer is the most obvious of these.


The VFC models run a zero hammer design, which I am not familiar with. There is a very stiff break point, and after that the slide cycles okay. But I would like to get this to as silky smooth as my bearing hammers in my TM builds.


From peoples experience, where are the failings/friction points in the zero hammer design?



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EDIT: Sorry, feel like I came into this thread all wrong with not much to add to your actual questions. Oh well... :( 


Unsure if the TM/WE Glock mags actually are directly cross compatible with Umarex/VFC ones? :o 

Right, recalled seeing a picture for this actually. Googled "airsoft glock magazine compatibility".

Says yay, but maybe nay? :o

Might be as you suspect that there is something just a little bit off that makes it more apparent in cold conditions.




As for the hammer. I am guessing the problem is as usual when you ease the slide forward from the most rearward position and it gets stuck right as the middle of the BBU is passing over the hammer "bearing" (in this case the Zero Hammer "wheel")?

Kind of funny because that is exactly what the Zero Hammer design is supposed to alleviate 😛

Semi OT: I got a really nice tip in a comment on my YouTube channel from a Spanish airsoft guy but that is pretty much how to make a TM/WE hammer wheel in to a "true" "Zero Hammer" which looks very impressive but kind of technical to get right.



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Yeah I’ve seen that chart. I had 0 feed problems, but did have gas leaks. I’m fairly sure the standard advice is due to the flat router on the mags, but rounded shape of the nozzle, hence my changing them all to Curved routers. Although I’m not sure the curve of the Tm spec nozzle is a smaller curve than the VFC, but that’s a separate issue.

Actually no, the only point of friction, is the initial pull, as if the hammer spring is too strong, but definitely feels like a rough edge rather than a spring. Zero issues with the slide travelling forward

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Oh right. So the racking of the slide to cock and lock back the hammer is what you are talking about.

Seeing that reminds me, I have that same thing on my Umarex Glock 19 GEN4 and I kind of laughed when I racked it because normally the slide is sticky in that position going forwards but now on these it's when the slide is going back.

I can have a look at mine and see if I can figure out what that is from.

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On the PPQ the zero hammer works well, but that isn't the problem.  The problem is that the irregular shape of the zero hammer increases blowback housing deformation/breakage particularly when the sharp end of the zero hammer impacts on the blowback housing.  

On the standard airsoft glocks, with a bushing hammer, the recoiling force is spread over a larger area and hence the blowback housing deformations is less severe.  The friction observed with a bushing hammer can be fixed by changing the slope of the last 1cm of travel on the bottom of the blowback housing.  As you will observe, it is both raised and has an sharp angular edge, once the edge has been rounded and the raised portion is lowered, both the blowback and return stroke will be smooth.

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^^ I was just looking at my WE Glock 19 GEN5 BBU and hammer system and observed just that regarding the friction and was thinking of smoothing out the "hammer cocking hump" on the bottom of the BBU.

But, WARNING, do NOT remove to much of that bump or slope as it will cause the BBU to not push the hammer wheel down far enough to cock the hammer properly. I've done that once 😛 

Dangit, semi OT again 😐 

Sorry wood man.

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Okay so whilst changing all the feed lips and routers, I discovered that the problem is not the hammer, it’s the disconnect or linked to the trigger.

After pulling the trigger, it stays back. As it should. The slide then begins to retract, and once the blowback unit his the disconnector tip, that’s where the friction starts.

If you do a mini rack to bring the trigger forward, without engaging the hammer, then rack the slide again fully, the motion is pretty smooth. Never had this issue before!

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Here’s the issue in picture. First, the Umarex design where there is a gap between the rear of the blowback unit, and the disconnector.

The slide comes back, and the 2 parts collide at a 45° angle to one another. Causing a definite sticking point.


The TM version the disconnector is always touching the blowback unit. The cycle starts, there is no collision.


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For your reference:


I have 2 VFC/UX G19s.  One is a Gen3 and another Gen4.  The Gen 3's a scrap gun so I'm waiting for a recoil spring guide so it's not functional yet.


The Gen4 G19 doesn't fit the TM G19 mag (too big, can't fit it all the way into the frame) and my prowin TM mags fit, function dry firing but it doesn't feed bbs.  Seems like the nozzle pusher's not low enough to push the bbs out of the mag.

Surprisingly the VFC G19 mags work with the TM G19 without any issues.

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