G&G M4 Feeding/Shooting Problem

[Hannibal]

Help!!

So, I took apart my new G&G M4 CQB-S to downgrade the spring to make it indoor safe and am having the following problem:

On Semi: When the trigger is pulled the first time, it emits a quiet click, and doesn't fire. On the next trigger pull, it fires cleanly and a second bb rolls out of the barrel immediately afterward. I'm assuming it is double feeding or something and his is actually the second bb that it rolling out after the second shot. This happens every time in semi.

On Full: Firing seems fine, except that the occasional bb rolls out of the barrel. When switching back to semi, the first trigger pull lets of a full auto burst, then it reverts back to the above semi-auto problem.

I'm using a 9.6v 1700mah battery. the new spring is a downgrade - a 1J Systema that should put it shooting at around 310-320fps. I didn't mess around with anything in the feed/hop up areas when I took the gun apart, and everything in the gearbox seem to be in the right place. There is no grinding or other bad noises either.

So - any ideas??

Hannibal

[scurvythepirate]

Is this the stock battery that it comes with?
If not, what battery do you have?

[audi_bhoy]

Sorry for this question but, are you familiar with V2 Mechbox? First times I unassembled mine the anti-reversal latch spring blowed out, and I had to make a custom one before receiving the new one, and the custom wasn't strong enough, causing a double-feed issue.

[Hannibal]

No - it was an upgrade battery, the gun doesn't come with one - this one should be more than enough to power the gun...

[Hannibal]

Hmm - I checked the latch when I opened it to check what was wrong, maybe I should try to put some more pressure on the anti-reversal spring somehow...

[audi_bhoy]

When the gearbox is assembled into the gun, turn it upside down, so you can see the hop-up entry for BBs, and then cycle it once in semi. The air nozzle normal starting position is backed, so it allows 1 BB to enter as soon as the mag is in.

Look carefully to the air nozzle when cycling in semi. If it goes back and then finishes by going forward at the end of the cycling, the anti-reverse could be the problem. This is what I've experience, otherwise I could not help you without having it in my hand. Hopefully it will help you!

[Hannibal]

Haha! Thanks for your advice everyone... In the end it was the anti-reversal latch, the spring was hung up on a wire that had popped out of it's groove and wasn't engaging... Stupid, I should have noticed it. Now seems to be working perfectly.
Cheers!

[audi_bhoy]

Great! Have fun now!!