Reviews: JG / CYMA 8mm Reinforced Gearbox for M4 M16 Series Airsoft AEG with Mosfet - Rear Wired

$70.00 $59.50

8 Customer Reviews
Model: GB-M4-MOS8mm-B
Location: U11-109

Displaying 1 to 8 (of 8 reviews)

by Neal R. on 2014-06-02 20:14:28
"Just got mine today it looks different from the picture and has a aps MOSFET (decent) but only thing I'm having problems with is getting the motor to fit into it I think the MOSFET wiring and soldering is getting in the way of the motor gear and I can't get the cap on to suck the motor up in there but everything else seems fine haven't got to shoot due to motor not being able to fit good or something I got the G&P 120 motor might have been worth to have just gotten a whole new pro kit receiver motor gearbox and all for 120
by Jorge F. on 2014-05-26 19:13:35
"This is an excellent gearbox so far; although when I received it, it did have a slight problem. It would fire on its own! I was thinking of RMAing it, but I decided I didn't want to wait, so I opened it up, and something corrected itself automatically. I replaced a few parts (piston with metal teeth, bore up piston head and cylinder head and air nozzle with o-ring) and now it works great.

Pros:
Pre shimmed / lubed
Spring guide notches are big (very helpful when assembling)
Strong tappet plate
Mosfet
Reinforced gearbox shell
Bearings (not ball bearings)
Gearbox screws (phillips heads, :P)
Easy takedown
Shoots hard (I haven't chronoed though)
Works very smoothly

Irritating things:
Putting the mosfet in the buffer tube
Wiring is a bit long, but it works
When assembling, it is hard to keep the trigger in place
Motor wire connectors aren't bent (I had to bend them myself)

Cons:
Plastic piston (has one metal tooth) - replaced with metal- toothed piston
Air nozzle (no o-ring) - replaced with an air nozzle with o-ring

I am thinking about getting another one of these gearboxes :D
by Brad B. on 2013-10-08 19:04:06
"Some of the below review seem outdated mentioning what seem to be JG's older gearbox from 2010. I am sure evike gets these from JG with their orders of guns and these are the gearbox found inside a JG or Echo1 M4 carbine. It has 8mm bushing, my selector plate is black instead of yellow like the image and the mosfet has a nice hard casing to protect it from accidentals.

415 FPS out of the box on my new custom M4 running a stock JG 363mm barrel.

Over all, the item work as expected. Good strong parts and gearbox.

Great deal with a nice mosfet.
by jerry W. on 2012-11-08 17:49:55
"I dropped this gearbox in my jg m4,with a 9.6 battery,it punched half way through a boiling pot!!
Very good gearbox,i will be ordering another.
by Joel H. on 2012-10-01 17:32:44
"Amazing gearbox! Popped it into my wounded JG M16A4 and it has brought the gun back to life! The rate of fire is almost doubled compared to the original JG gearbox and sometimes it shoots so fast that the mag can't load a bb in time!!! (Which may sound bad but with a spring low-cap mag it would work just perfectly. It makes me happy though!) Anyway the only con is that the battery connector is mini-type and did not fit the battery I had so BEWARE! It was an easy fix by just soldering the old connector to the new wires. It's like putting an M16 into the Pack-A-Punch machine, it really strikes some fear into those radical Muslims!
by Jeffrey T. on 2012-04-15 06:14:06
"I am a retailer buying several thousand dollars of product from Evike and continue to do so. I have purchased 3 of these gear boxes. They all had issues with poor shimming and poor quality parts. I sold the bodies to customers who had bought the same gearbox and had the shell crack. Hopefully the next batch of gearboxes JG puts out are better. I give this particular gearbox and big thumbs down. Overall JG makes excellent quality products, I still buy a ton of JG products, just not this gearbox.
by kyle c. on 2011-12-04 14:50:40
"Wonderful gear box. I am excited to put it in my echo1 stag 15 m4. With this kind of fps no one will be dishonest about being hit
by jared a. on 2010-12-01 18:02:21
"This gearbox is very good. i have taken it apart for a spring swap and had this chance to view the parts closely ( i will list the parts and quality at the end). I bought the gearbox for a g&g raider and had to customize the wires in order to makre it work. but afetr all of the cusomizing i have found it to be an excellant gearbox for the money.

part/quality
m130 spring/good
bearing bushings (not ball bearing)/excellent
torque gears/excellent
ported cylinder/excellent
plastic cylinder head (one o-ring)/good
air nozzle (no o-ring)/good
plastic piston with full metal teeth (second tooth is not removed)/excellent
plastic piston head (not sure if it is ball bearing)/excellent
full metal spring guide (not ball bearing)/excellent
standard v2 tappet plate/good
standard trigger box/good
standard anti-reversal latch/good
Reinforced steel gearbox shell/excellent(only time will tell)
silver low resistance wiring/excellent

Only time will tell for the durability of this gearbox, please remember you may not get a gearbox that is as duable due to factory issues, so be ready for the liability. overall great gearbox.

Displaying 1 to 8 (of 8 reviews)