Matrix Advanced 8mm M4 / M16 Version 2 Quick Change Spring Gearbox for Airsoft AEG Rifles (460-500fps) - Rear Wired

"Put this in a cheap colt gun and it immediately started sounding better along with an amazing trigger response and rate of fire with a faster motor too

"Put this Gearbox in my APS almost a year ago now and it's still running like a champ. Getting a consistent 445-450fps and so far I haven't needed to change the spring yet. I usually prefer to not use drop-ins but I wanted instant gratification without troubleshooting and I was extremely pleased with the performance.

"I recently bought this gearbox for my G&G combat machine cm16, the gearbox required no modifications to fix but it was very difficult to get the pin through the lower receiver after that everything else for perfectly.

The stock spring is actually pretty good
I got 430 fps with .25g bbs and 390 with 390fps and I imagine It would shoot about 470 fps with .20g bbs

I upgraded my motor to a high torque motor And the gearbox sounds great and works flawless so far, but I haven't had much play time on the gearbox. The gearbox feels like quality from the outside, it's substancially heavier than the stock g&g gearbox.
The wires are pretty short which is annoying but it's useable

All in all, I would recommend this for an upgrade it's easy way to get the most out of your gun. Its easy to install and performs as advertised.

"I dropped this into my G&G M4 A1 after the old gear box broke and it worked alright, the trigger response was meh but after a few games it stopped cycling. I discovered the spring that comes with the gear box wasn't strong enough to reset the Piston all the way so the gears were just spinning free. After looking at the spring that comes with the gear box it's absolutely trash but I did have a m110 and when I put that in the box worked unbelievably. Trigger response was unbelievably snappy for a system without a mosfet and it's so smooth. If you're going to pick this gun up I suggest grabbing a better spring to go with it but if you do you won't be disappointed.

Pros
Snappy trigger response
Smooth cycle every time
Feels great and gives a nice bit of kick without needing a blowback unit
Quick change spring system makes getting that old trash spring out ez

Cons
Spring is unusable
A bit pricy

"Extremely good gearbox right of the box. No need to really touch anything. The description for the FPS is accurate. Had a Krytac hop-up and nub, maple leaf bucking (70 degree), and a raptors tactical 6.02mm, 407mm inner barrel and it shot 435 on a .25G. I ordered a Lonex High Torque motor with it as well.

Installed an M115 from Mad Dog (UK parts company) and it was shooting 380 on a .25G.

I eventually installed the GATE MERF 3.2 Mosfet unit and the gun is shooting flawlessly.
Another positive i'd like to point out about the gearbox is that the Spring Guide is ball bearing, which not too many QD spring boxes have.
Worth the $120!

"Wonderful gearbox. Definitely expensive for a gearbox, but I just lubed it up, put in a new spring, and it purrs all day long without a problem. Absolutely phenomenal product that I would recommend. I'll will note that the wires out the rear are abnormally long, so if you're tight for battery space it might be a bit annoying to fit all the wire slack in.

"I have this gearbox in both of my G&G builds and it is perfect for CQB or DMR rolls. It is built like a tank and has never failed on me. There is a reason I have bought 2 of them, love them!

"I ordered 2 of these and i am impressed with how nice they are. Only complaint but not really a complaint is i added a little bit more grease but rather have to add then clean and add. I took it apart to check it over so all parts are good. shoots at 415 in my M4 with included spring and .20 BB

"Just got this, put it in my M4 CQB-R and works amazingly! Well built, good construction, high FPS.

"Very nice gear box. Popped it right in to my G&P. Only disappointment is the fps. Stock hop up and stock 208mm barrel. Shooting 405fps with .20 and 385fps with .23. I have a new hop up and barrel on the way. I’m expecting maybe 10fps more from the barrel and hop up. Also considering a Systema m140 spring to see where that takes it.

"Just put this in my CYMA mk.12. Shoots extremely well. Great range, can reach probably about 230 feet with stock hop and barrel, fairly solid consistency and accuracy. However, the fps is not the advertised 460. With .25 bbs I was shooting only 355 fps. I know the stock hop and barrel aren't helping, but it shouldn't be more than 100 under.

"great gearbox. high rps with a 30k motor. great t rigger response. but the motor connectors both broke within 3 hrs of eachother during a game. luckily i came prepared with more connectors, a crimping tool and a lighter for heat shrink and was back in the game in 10 minutes. this gearbox is almost as much as most common aegs, i thing 6 bucks could have been spared for some better connectors.

"i dont have the gearbox in my hands

"It shot good and all, but the motor connection broke. I don't know if I got a lemon, but honestly I'm upset considering the price tag