M4 tigger freez/lock

[MilanWG]

Hey whats up everyone.

I have a G&P custom M4 with a Systema complete Mech-Box & Motor Turbo Set internals.

http://www.uncompany.com/images/sys-cmb-t-a2_big.jpg

I just shot off a couple burts on auto and my AEGs trigger is now locked/frozen. What did I do? There doesn't seem to be a bb jammed. Is it something with the internals?

Help would be much appreciated
– Milan

[TokyoSeven]

If changing back and forth a few times between safe semi and auto doesnt help, then yes something most likely has mechanically failed. It could be a few reasons, perhaps your selector plate has failed to engage properly and you are now stock in semi, or perhaps something inside the mechbox physically jammed or boke.

[MilanWG]

Thanks for the response.

When I flip it to auto, the trigger doesn't feel locked. On semi it is still locked. What should I do? Take it apart?

Thanks again:banghead:

[TokyoSeven]

So when you engage the selector into an alternate firing mode it provdes a small amount of give for the trigger? It could be that your selector plate is not engaging correctly. Perhaps there is an abstruction, it is broken or has become misaligned. However it still stands that the error could still be comming from inside the mechbox.

If its with in your abilities, I would recommened taking it about to trouble shoot.

[MilanWG]

Thanks for the response TokyoSeven, I appreciate your help.

I just tried a new, fully charged battery and it worked. Both semi and auto function and the trigger is "un-frozen"

By connecting a new, freshly charged battery, did I fix the problem?
Was the problem that I just drained the battery that I was previously using with my auto fire bursts?

Thanks again opcorn:

[SultanOfShwing]

I had a similar problem with my TM SR-16. Changing the battery to a fully charged one eliminated the problem and I haven't encounterde it since.

[TokyoSeven]

Im glad to hear your solution is fixed.

I didnt even think it was a battery issue, since I just assumed that the battery was charged already since you had stated that you only fired a few shots. Was there any clicking sounds when your trigger initially froze up?

[MilanWG]

I fired almost an entire 75rnd pmag in groups of auto. But the battery inside my retractable stock was not fresh and had been used for test-shooting and had been sitting in the rifle for a couple days.

I did not hear any"clicking sounds" when the trigger initially froze up, nor did I hear anything rattling around inside. As soon as I connected the fresh battery, it worked A-OK.

This is actually the second time this has happened. The first time I just left the rifle and it went back to normal about 30min later...

Thanks for everyone's help and past experiences/observations.
Much appreciated

[Flatlander]

So if I understand you right, your trigger is physically unable to be pulled, correct?

Couple things:

- The semi auto mechanism is quite a funny system and sometimes if the gears stop in a particular position you will not be able to shoot in semi. Switching to full auto solves this problem. This is most common when 'feathering' the trigger in semi auto and is more prodominant in v3's but happens in v2's also.

- The above may be your problem, but from what you've described I don't think so. I installed a drop in systema mechbox once and had the problem in which the trigger would phyically jam in the semi position but auto was fine - if I recall correctly, it was a while ago. I thought it was a selector problem and tore the gun and mechbox apart countless times. I finally found out that it was actually the trigger switch assembly causing the problem. I *think* it was the little piece with the electrical blade that is pushed between the contacts by the actual trigger. Anyways, I can't find any good pictures to reference but there was a tiny little wedge on the piece that is supposed to slide up/down over something else. However, this wedge had a very blunt tip - I compared it to another assembly I had kicking around to confirm improper shape - and would jam instead of slide nicely. Anyways, it took a bit of filing to get the proper wedge shape and she worked like a charm after.

Hopefully the last one isn't your case because you'll have to crack open the mechbox. However, you have a heads up to look out for that wedge thing where as I spent hours upon hours trying to figure out what the hell was going on! :banghead:

[Flatlander]

Originally Posted by beatbaker

I fired almost an entire 75rnd pmag in groups of auto. But the battery inside my retractable stock was not fresh and had been used for test-shooting and had been sitting in the rifle for a couple days.

I did not hear any"clicking sounds" when the trigger initially froze up, nor did I hear anything rattling around inside. As soon as I connected the fresh battery, it worked A-OK.

This is actually the second time this has happened. The first time I just left the rifle and it went back to normal about 30min later...

Thanks for everyone's help and past experiences/observations.
Much appreciated

Unfortunately, I'm pretty sure your fresh battery has nothing to do with it.

Does your trigger feel 'sticky' initially?

Possibly your wedge I described is not as blunt as the one I worked on and only gets jammed on occasion. Maybe a bit of use will smoothen it out and you won't have to open it up.

[MilanWG]

Thanks for the detailed response Flatlander. I appreciate it.

When you ask, does my trigger feel sticky, how would you define sticky?

And just a heads up if it helps, this is an almost brand new build. All the parts are almost new. Ive had the rifle for a couple weeks now...

Thanks again everyone, I really do appreciate the feedback

[Flatlander]

As in when in the intial pull does it feel like it wants to jam, then all of a sudden let go (even occasionally)? Or is everything buttery smooth all the time and then just locks up for no apparent reason?

The systema mechbox I discovered the wedge problem was brand new, fresh out of the packaging so it didn't occur from use.

[MilanWG]

The trigger doesn't feel like its going to jam, but it is a little stiff. Stiffer than any of my GBB pistols.

Hope that helps...

Thanks again

[m102404]

Milan,

The main issue at this point is that...nothing wonky inside fixes itself with continual usage. If something is off inside...it'll either be iffy or it'll get worse.

There's a lot of good advice here already.

1. Start with a fresh battery...you've got a KA Mod stock 9.6v 1400mah mini. If it's the new one...make sure it has a solid low amp setting full charge.

2. Don't feather the trigger. Regardless of semi or full...you need to pull the trigger all the way back to get the switch assembly block far enough forward to make a solid electrical connection and to get it in a spot where the cut over lever hook can knock it out of position reliably.

3. From safe...turn the selector to full...it should a smooth rotation with no binding. Fire a burst (don't need more than 3-4 shots). Then slowly turn the selector back to semi (be sure not to turn it past semi). Fire 1 full-trigger pull semi shot...how did the trigger pull (smoothness, resistance, any sticky points) compare to the full auto burst? If it felt the same that's good. If it felt different, then something is hanging up the trigger...most likely the safety.

4. Repeat the same thing as 3...but start with semi...then compare to full auto.

Let me know how it goes.
Best of luck,

Tys

[MilanWG]

Thanks Tyson, really appreciate the super-informative and helpful response.

I will let you know how it goes.

Thanks also to everyone else for the tips. ASC members are the bees-knees

Update:

I tried cycling from auto to semi and semi to auto as recommend and I didn't notice any difference in the trigger. When I actually flip the selector from safe-to-semi-to-auto it is not super smooth and clicks on each setting...