TM G17 firing problems.

[wind953]

Hello,

I've been having some problems with my TM glock 17, where the amount of gas wouldn't output consistently. I'd take one shot, and everything cycles fully and crisp, but usually on the second to third shot, there isn't enough gas to cycle the slide at all. The BB in the chamber gets pushed out (albeit probably weakly), but the amount of gas left over is too weak to carry the slide back.

At first I thought it was because I didn't allow my mag time to warm up after charging, and it seemed to solve the problem. But that quickly changed. It's a recurring problem.

The weird thing is, I find that after each shot, if I release the mag and then push it back in, it's fine. Obviously I don't want to do this every time or I might as well use a springer.

I suspect it may be due to the valve knocker not resetting after each slide cycle. Reinserting the mag will basically have the valve of the mag brush up against the knocker and push it back in, ready for the next shot. If this step wasn't done, the valve knocker does not reset, and it basically stays in its protruded position resting up against the gas valve, which means pulling the trigger will shake the knocker forward enough to squeeze out a tiny bit more gas. I'm not sure if this is the case though, and wouldn't know how to go about fixing it if it is.

Anybody has experience with TM G17 internals can help out?

Thanks.

[Styrak]

So if you remove the mag and put it back in each time, you can fire off an entire mag of BB's at full power?

[wind953]

Oops sorry I wasn't being clear. If I don't do that after one shot, the following shot will have that problem I described. But if I release and insert mag after that first shot, the following immediate shot will be fine. Then I have to do the procedure again for the third shot to work. So basically it's like operating a springer, but instead of racking the slide, I have to release/insert mag.

[Styrak]

But you can fire off an entire mag at full power with that method?
That was my question.

[pusangani]

and each time you are ONLY removing mag, and NOT racking the slide?

sounds like valve knocker/spring is off and is being reset

not too familiar with the glock platform, but if there's a valve knocker disconnector on those guns it could be that too.

try taking off slide, put empty mag in (no gas or bb's) cocking and pulling trigger, look into the trigger mechs and see if everything is where it should be

remove mag and see where the knocker is positioned

not a solution but a start.

[wind953]

@Styrak

Yes, I can shoot normally with that method, and full mag fills of gas last as long as they are supposed to.


@pusangani

Yes each time I am only pushing the mag release and push the mag back in as soon as it's loose. The slide will have already been racked from cycling after that first shot. It's fire -> slide cycles normally -> release mag -> push back in -> repeat.

I've tried taking off the slide and pulling the trigger with the mag in. As you would expect, the knocker stays pushing on the valve and the gas just keeps gushing out, since the knocker was never reset due to absence of slide.
I can reset the knocker by using my fingers. I suspect it's the slide somehow not doing its job, and I can't really observe that unless I'm able to see inside and in slowmo while the slide is cycling during firing.


Taking images from the Book of Toy Guns Disassembly (sorry for the shitty cut/paste job)...



The left image shows 1) the knocker resetter and 2) the hammer mech. The slide should do two things when racking back: push on the knocker resetter, resetting the knocker, and cock back the hammer. I suspect the first job isn't being done for some reason.
The arrow in the right image points to where the knocker is (it's in its protruded position). I've inspected that position with where my mag's valve is when inserted, and things seem to line up correctly. The spring and the thingy in that image should be the resetter from 1) in left image.

My question is this...If I am able to use my finger to reset the thing, then the spring is working as it should be right? Would there be a reason that the slide isn't able to push on the resetter far enough to reset it? Also please note that this slide is a PGC slide with some filing done to it by the previous owner. Is that important?

Maybe I should just ship this off to a gun doc and save the headaches, but I've never done that before, and don't know how expensive that might be...

[pusangani]

Try to take a look at one that is working properly, maybe at a game or somehting ask someone who has one to bring theirs so you can compare the 2 guns, my money is on the valve knocker disconnector not working properly, the top may be worn down so it's not making proper contact with the bbu as it goes by during slide cycles


*edit*

When did this start? when was the last time it worked properly, any mods done to gun in the time in between?

[wind953]

Is the valve knocker disconnector the "knocker resetter" that I described in the images? Sorry I'm not sure what the correct terminologies are. And what is the bbu?

This started pretty much as soon as I bought it off the previous owner. The problem kinda came up and then went away for a little while then back again. I've really only done brief plinking with this gun so far (~80 shots). No mods were done since I bought it. I've cleaned and lubed everything, but that's about it. The only mods that were done was filing down the PGC slide to get it to fit properly, according to the previous owner.

[Shirley]

All I know is the problem is the disconnector.. That's what causes the weak shots.

[wind953]

How difficult is it to get that part replaced?

[audi_bhoy]

I might have a hint. The valve knocker has a 2 holes. one might be broken, has I already seen on a TM G17 clone. One hole is for the pin, and the other one is for a spring. If it is broken, it can cause your problem.

http://www.wgcshop.com/WGC_Shop/images/sd_pt_s727_m.jpg

[RacingManiac]

There is a torsion spring that's suppose to hook into the lower hole, pulling it back. The hammer strikes the it when you pull the trigger(well not so much "strikes, it works more like a cam lobe rolling onto it), opening the valve, the knocker will stay forward til the resetter is tripped and as it moves down the side protrusion of the knocker is not being blocked(and hammer re-cocked) and the torsion spring spring will pull it back. The top slot rides on a cross pin and is the limiter of its travel. TM Glock AFAIK don't have a "disconnector" per se in the sense of the Hi-Capa/1911. Its trigger bar serves the dual purpose.

I am not sure what the issue is, as with anything its hard to judge over the web. A few questions though, how hot was it when you try to shoot? Is the hammer spring stock? For me personally the TM Glock have more of a common issue in light strike when the gas pressure is high, at least more so than Hi-Capa. Though your symptom is certainly different from what I've experienced....