M4 not firing

[Ghillieman]

The electronics are fine and the motor operates the gearbox fine. JG M4 loads the first bb into the hop-up chamber but will not fire it. It used to double feed like crazy until I changed the bucking and nub. The gun is really loud and makes a springy sounding thud when it fires. I don't know if there is too little compression or what the issue is. Help please [-o<

[carbon14c]

-it feeds
-it cycles
-barrel is not jammed
-bucking/hop unit is functioning


that is what i gathered from your post, is that correct?

[Ghillieman]

That's right. As soon as the first bb loads no more will load. I use my unjamming rod to clear the barrel and it happens all over again.

[Crono0001]

You make sure your tappet plate is okay?

[axisofoil]

Quite a few reasons this could happen. Here's a basic rundown.

tappet plate... is it broken??
nozzle's attachment to tappet plate
too hard of a bucking
too weak of a tappet plate return spring
you installed the bucking wrong
you have the hopup turned on up too high

[Ghillieman]

It used to double feed with the old bucking, when I swapped it out the double feed stopped all together. The bucking is a classic army and is rated up to 420 fps, at best guess this AEG only shoots 400. The hop-up is all the way down. I'l try lubing the snot out of it and see if that helps. Also I didn't notice the tappet plate having any problems at first glance when I cracked open the mechbox. I'll have a closer look. Thanks again.

[Crono0001]

Make sure the air nozzle is on the tappet plate correctly

[axisofoil]

try a different bucking maybe. just because it's new doesn't mean it works.

[Ranger_Robby]

I saw you used an unjamming tool and "oiled the hell out of it"..

if you werent careful you could have damaged the nozzle or knocked it out of place when unjamming the barrel. this could explain your description of lose of compression. open it up and make sure the nozzle is seated properly and is undamaged. also, when you oil the bucking it takes a few shots to clear out that oil if you over oiled it. this happened to me at a large event when I hastly over oiled my hop up bucking when switching barrels before I had to run to get it to chrono. it was fine after a few shots but it had to get cleared out to return you normal.. it miss and double fed and shot like crap until it was cleared out of extra oil. remember too much can be a bad thing.

[nynone]

From the original post, it sounds like either the bucking and/or tappet plate need replacing. If that's not the issue, check to make sure your air nozzle is seated on the tappet plate correctly. Having the nozzle seated incorrectly could be the issue if the tappet plate isn't pushing the nozzle forward either enough, or at all if the two aren't connected.

As for the noise, I'm sure it's a spring issue, as the spring may be a bit short, or just louder than you are used to. Since the rapid compression and decompression cause the spring to twist very quickly (which is natural of course), the twang may just be the spring re-seating itself on the spring guide or inside the piston. Either way, it wouldn't be a big deal. If it's short, that is a simple fix as well. Just get a new spring. Now, it may also be noted that if it's just the spring twisting with compression and decompression, a ball bearing spring guide would be a fix to help ease the noise. My CA does the same kind of thing, just not very loud. I don't mind the twang, so I've no reason to install anything for it.

Hopefully you can figure it out easily. Sounds like an easy fix.

[Ghillieman]

Again thank you for the insight. The spring guide is a ballbearing type. It pisses me off that I tore apart the mechbox and looked at everything but the tappet plate and air nozzle. Oh well. I'll dig into this thing a little more when I get the time, but I will keep you updated. Thanks again for all the help guys.

[Ghillieman]

I'm going to say that the tappet plate was seated wrong. I'm not sure. I broke into the mechbox and removed the tappet plate. I examined it and there seemed to be nothing wrong with it. I put some lube inside the air nozzle and ran it up and down on the cylinder head a bit, then put everything back together. I fired a couple of shots on semi and didn't notice any bbs coming out but that was because of the crappy light. I threw it on auto and shot at a dark target and now it is shooting ropes. Thanks again for all your help guys.

[nynone]

Yay for online troubleshooting!!!!!!!  [smilie=armata_pdt_35.gif]

[ScaR_SnipeZ]

pull out the mag, take apart the 2 receivers and see if there is a bb lodged inside where the mag would normally load. sometimes if you have silicone there it will snag a bb and you wont be able to shoot.

[d.prather]

He stated it's already fixed