WE MP5 / Apache semi issue

[war22air]

I have had a problem with my WE mp5 for a while now, essentially when it is set to semi / burst it will go straight into uncontrollable full-auto (firing without trigger pull).

I bought a new trigger assembly from kyairsoft but this has the same issue, I then bought a new selector (part 20 I believe) and that helped for a while but the problem quickly returned.

I was recommended by kyairsoft to buy part #33 which is a sear I believe but again the problem remains. Finally I bought a real firearm elbow spring for the sear and yet still the same issue.

Ive completely run out of ideas and would appreciate any help from anybody that may have experienced a similar issue.

 

[Wo1f]

How worn is the bolt?

 

[war22air]

I suspected the bolt was worn somewhere but I couldn't figure how that would affect the cycling. I can upload an image if you want but it seems it pretty good shape but for the odd mark.

 

[Wo1f]

Is the disconnector new?

 

[war22air]

The whole assembly was new, as for the disconnector I'm not sure what part that is (I'm guessing the small lever on the front right)

 

[Immortal]

If you find it is part of the trigger assembly at fault then Z-parts make a hardened steel kit either as seperate parts or a full kit. It replaces all the weak parts; sears, hammer etc

Uncontrolled slam firing really sounds like a sear not engaging/or slipping - wether it's the sear or the part it's engaging or the part that puts the sear in a position to engage etc is hard to know without seeing photos.

Burst fire is a mechanical design on the MP5 so you have to hold the trigger to complete the cycle. If it's running away on that then it's not engaging the burst select position either. The fire selector is pretty weak IMO on these RIFs.

I assume it makes no odds what mag you put in? Or different gases?

Sorry if that seems like more questions and babble than answers.

 

[war22air]

Thanks for the suggestions.

The magazines nor gas make any difference to this problem. The thing is upon inspection the trigger assembly parts have no wear whatsoever (it was new) so it's hard to see what is at fault.

I also purchased this but the part it replaced was not worn or damaged.

As for the Z-parts kit, I was aware of this but the price and the fact that I already had new WE parts put me off.

What specific photos would you want? it's relatively straightforward to take apart.

Thanks

 

[Guest]

Hmm, no experience with your gun, but my issues with gbb firing are often spring related.

Have you replaced all the springs?

 

[war22air]

Hmm, no experience with your gun, but my issues with gbb firing are often spring related.

Have you replaced all the springs?

Well I assumed all the springs were still good as they came in the new trigger assembly, also I had bought one of these but it didn't help (despite being far stiffer).

 

[Guest]

Well I assumed all the springs were still good as they came in the new trigger assembly, also I had bought one of these but it didn't help (despite being far stiffer).

Like I said, I don’t know your gun, but I always start with standard everything when I have an issue

 

[Immortal]

<SNIP>

What specific photos would you want? it's relatively straightforward to take apart.

Thanks

Well, my WE Apache is an MP5k model and I'm not sure which yours is (unless it is just an MP5...lol).

I'm no expert that's for sure but if you take a photo from a top down view into the lower receiver and try to show the fire selector plus trigger group (perhaps with the selector in a position it goes runaway on) I'll compare it to mine tommorow. You said the bolt carriers in good nick so may aswell skip that photo. Also anything else you consider of interest. 

It'll be a spot the difference. It's a place to start if you wish to anyway...

 

[war22air]

Sure will do thanks, it goes runaway on any of the 3 selections

 

[GemsHD]

Lol it's obviously a gear box and motor mismatch issue, change the bevel gear and use a lower V battery. Damn scrub doesn't know anything.

 

[war22air]

View attachment 40020

View attachment 40021

View attachment 40022

 

[Prisce]

Lol it's obviously a gear box and motor mismatch issue, change the bevel gear and use a lower V battery. Damn scrub doesn't know anything.

Please @proffrink can I have a D’oh emoji.... pleaseeee....

 

[evilrobotshane]

I’m having a similar but different problem with mine; the trigger stops responding after a few shots on semi-auto, but will work on three-round burst for a little, then that also stops working (as if empty) and only full-auto works. I haven’t replaced anything from stock and am new to gas blow-back rifles unfortunately. 

 

[GemsHD]

Please @proffrink can I have a D’oh emoji.... pleaseeee....

I second this, would be perfect for @war22air's thread when the answer is so obviously the piston has been stripped... smh

(I want to take this moment to point out that War22air is a good friend of mine and I know absolutely nothing about GBBR repair)

 

[Prisce]

I second this, would be perfect for @war22air's thread when the answer is so obviously the piston has been stripped... smh

(I want to take this moment to point out that War22air is a good friend of mine and I know absolutely nothing about GBBR repair)

Oh I had figured, I just want a D’oh emoji for this exact scenario.

 

[Immortal]

I'll open my mp5 up tommorow to compare to your photos.