G&G M4 help!
 

So, i bought this gun from the classifieds, and long story short, it doesn't shoot.

This is my first AEG, so I wasn't too sure what to do, so i disassembled the gearbox, and found out nothing was wrong in the gearbox. But when i pull the trigger, all i hear is a little twitch (like if the battery was barely charged). Even when i fully charge the batteries, same result. I have no idea what is wrong..

thanks in advance for any help

I have a G&G M4 as well and the same thing that twitch noise happened to me as well. Turned out to that my cheap ass wall charger wasnt charging my batteries so i replaced the charger with a better one. No probs since. Hope this helps.

I have a universal smart charger...

Is your gear shimming correct? Also try to borrow another battery so you can test it to make sure it isn't your battery

Those are usually the only 2 things that cause that twitch, is your gears are to tight and the motor can't move it or your battery is out of juice

hm... well the i do have 2 sets of batteries, but i'm not sure on how to shim my gun properly.. any guide?

There is some shimming guides on YouTube
Prodigy's AEG Shimming Guide - How to Shim an AEG Mechbox -ASTKilo23- - YouTube

I recently had this problem and it was due to shimming, make sure you didnt drop any shims if your gears fell out at all, and make sure they are aligned properly with your motor pinion

You have a piece of crap with "charger" written on it...

If you used that charger for a few months on your batteries, they are most likely dead.

Borrow a battery from someone and try again.

Also try to "unscrew" the adjustment screw right in the middle under the pistol grip by about 1/2 turn. If that fix it, it's the motor adjustment.