No luck ! M4
 

Humm the last month i have put a M203 Long on my TM M4 with a Metal Body. What a pain !

Last day, i tried to shoot some mag to keep her fresh. After a mid-cap all things goes wrong and the gun have just stopped to work. At first a motor who try to turn gear and after that nothing.

I have take the gun apart with no graphic...yahoo to me. I have found some tape. Under the tape (connecter to gearbox) it was a shitty fuse connector with no fuse. I have cut this cable suspecting the problem. After 4 hour of trying replacing all thing together, i have fixed a new cable with a new connector. The gun was tested and just worked fine minus some problem.

#1 : The gear on the motor is a little stripped (still work)

#2 : The gearbox look like cracked

#3 : The metal body have a crack...

#4 : On full auto it work fine, on the semi it shoot 1-2-3-4 bb's at random in one shot.

My setup is a base tm gearbox with some upgrade to put it just below 350fps (guess the spring). I use a 9.6v battery with mid-cap King arms mag. Of course, the hop-up just goes off itself while firing.

The first 3 problems i just know it's a matter of time before anything will break in it. I just try to understand the #4. I lubbed the hop-up just in case. Maybe it's the battery, maybe it's the hop-up, maybe it's the mags...

If you already got this problem and can write some work in relation with, i thank you now !

Ok I had the same problem #4 on my JG m4. I thought it was the cut off lever so I replaced it with a systema one but that didn’t fix it at all :( I also replaced shims and bushings. So now I am just going to replace the whole gear box with a modify tune up kit because it really pissed me off (and I cant shim for @&%#). Now back to the problem. It can range from a bad shim job, to worn cutoff lever, to a bad selector plate, a messed wire set, a worn sector gear... and much more. I would take it to your local gun dock to make sure, but if you see any unusual warn parts then I suspect those are the ones that cause the problem.

The way i think you see number #4 it you pull the trigger for a single shot (selector on semi) and the gearbox cycle the number of time 1-2-3-4 with a bb on each shots.

On my side it's you put the gun on semi, you pull the trigger the piston just go back and forth one time and tadam shotgun effect 4 bb's, sometime one...totally random

oooo... that is really weird i would presume its you’re mag. Does the little dimple that keeps the BB's in the mag look worn or small?

If your gearbox is broken that will lead to all kinds of feed issues. I would suggest taking it to a gun doctor in your area before you fire the gun again. If your gearbox is broken and the gun still fires it will only be a matter of time before your hopup breaks. Gears or pistons can strip once the box is broken aswell.

AND your metal body is cracked.

This probably causes some alignment problems with the hop-up, and can be the cause of shotgun fire.

New gun.....yéééé !!

Or i change gearbox,hop-up set, metal body...around 400$ shipped. Price of a new gun. Damnation why all thing can go right at the same time...always something bad to take care to not be totally happy with the good thing when they happen !