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Airsoft Systems ASCU Fire Control System for Ver 2 AEG Gearbox - Gen 4

14 Customer Reviews

by Lisa Q. on 04/15/2017
"I bought a custom gun off of Ebay with this installed by a likely extremely experienced tech, because this thing worked flawlessly. It has fantastic trigger response, not the best, but it should keep up with any fast trigger pulls in the field. Also, I don't know if it helps, but I'm pretty sure a small FET was installed in my stock as well, after a change to a deans connector. Never over/undercycles when battery is full, great control there. I used about 9.6 lipos with this, worked great. Also the damage protection shutoff when battery is really low/out works fine. I don't understand people's issues with this thing, but if you know what you're doing, buy this. Otherwise if you don't, I guess just buy a GATE Titan or BTC Spectre, of which I'm actually ordering a GATE Titan for my other personal custom m4.
by Chas G. on 09/12/2015
"I just finished installing the ASCU-2 Gen 4 into my heavily modified, Lonex based gun. The install was completely smooth and trouble free. Others here have said that they had to modify the unit to get it to fit into the shell, I did not experience any of that at all. The unit slide right into my Lonex gearbox perfectly! Everything fit like it was made to fit into my gearbox shell. The only modification I made was changing out the small Tamiya battery connector to a Deans connector. Super simple for me.

I have a Lonex A1 motor in this gun and figured that would be considered an up graded motor so I left the anti-reversal latch out of my built and it worked perfectly.

I also had a SPEED trigger already in this gun and so with some minor tuning of the trigger throw I had it set to have an incredibility fast and very slight trigger pull to fire a shot. This system was made to take advantage of the SPEED triggers.

I simply followed all the instructions in the well thought out, English manual that comes with color pictures as well. So often in airsoft we buy stuff that has either useless or non-existent instructions. This fire control unit kit has a very well written (actually a couple typos, but who's counting) and easy to understand manual! Such a relief as there are a couple of things that if you install this wrong you can destroy your unit.

After it was in and the gun put back together I test fired it quite a bit and it worked flawlessly! In a week I will be using this gun at a large MILSIM event and hope to see the full nature of this system in action.

-Easy to install
-Instantaneous trigger response!
-Well thought out system
-3 round burst FTW!
-Detailed manual

-Needs to have an up-rated motor to work properly and as designed
-Delay between trigger pulls in semi and 3rd burst mode (probably a designed in feature, but I wish it had less delay between pulls. I am nit-picking here.)
by Linda S. on 06/15/2014
"Love this unit! It takes some modification to fit but it works fantastic. At first mine would only shoot half a shot then beep twice. I had new gears shimmed so well that they rotated freely, an M170 Devil Jet motor, and installed the unit correctly and had a brand new FLAME 11.1v Lipo. I contacted ASCU and apparently this is a known issue. All you need to do is cut the notches off the black piece on top of the cutoff sensor unit (it is shaped like an L). The notches push the top and bottom portions of the unit together too tightly and cause the unit to "misread" information gained from the cut off sensor. So once you flatten out that piece, it should work.

-Easy install (modifications can be done with a file and are simple)
-Very good trigger response
-Makes your AEG sound like a PTW
-Protects your battery, motor, and internal components
-Hair trigger mods are easier
-3rd burst
-Semi Auto only for DMRs
-Limits how fast you can shoot on SEMI so you do not over cycle
-Good wiring, and plenty long
-Durable motor contacts
-No soldering
-No anti-reversal latch means much smoother cycles!

-$100 for basic functions
-Very large, which is why the modifications are needed
-Wires are big (I had to modify my buffer tube and drill a larger hole)
-Need to shim your gears well, have a strong battery, have a monster of a motor, and have a good AOE to use this thing effectively and safely

Great internal upgrade. Best I've ever installed. 5 stars.
by Asa H. on 08/02/2013
"!!!!BUY THIS!!! I put this in my VFC SCAR and i couldnt be happier with it.

Trigger pull
Trigger response
Three round burst
Uses a button instead of contacts
Easy to install

Many more....

I really dont have any but that it tells you that you dont need the anti reversal latch but you do.

Easy fix.
by Logun N. on 05/05/2013
"I have 2 of the Gen 2 versions of the ASCU and the Gen 3 is a big leap forward. The install is fairly smooth and strait forward. An upgraded motor was needed for all of my KWA guns to get the full benefit of the units. The Aim motor or TL 5000 high torque motors are a great compliment to the ASCU. With a high performance gun and 11.1 lipo the ASCU makes a lethal combination. You won't regret your investment!
by Dillon t. on 04/14/2013
"I had mine for a couple of weeks now. I love it!! It was only a little hard to install then normal wires. The only trouble I had is I always mess up on the programing. My m4 is shooting much faster and the trigger response is awesome. The plastic piece that get glued on the trigger was to small for my taste (took 3mm of movement to fire ). I found a bit larger piece of plastic, so I only have to move the trigger about 1mm.

-see features

-the tamiya plug is hard to fit through a buffer tube
-the instructions are a little hard to understand, I had to read them like 3 times to understand
by Steve G. on 05/19/2014
"Picked this guy up, was dead out of the box. Evike was very good about the RMA, got a new unit, and it is working really great.

Something to note: It seems you need to step your motor up quite a bit over what your spring is to be able to take advantage of removing the anti-reversal latch. If the motor buzzes twice after firing, its trying to tell you that your motor isn't strong enough.

The unit has a lever that makes contact with the sector gear to insure a full rotation every time you pull the trigger. This makes my DMR happy.
3 Round Burst is fun to play with!
Has Safe/Semi/Semi ability, good for the semi-auto sniper.
Its generally available. Been having a hard time tracking down other Fets that have internal mechanisms to detect sector gear movement.

Install can be a beast for the new Airsoft Tech. Some grinding may be required.
Need quite the hefty motor for all of the functions
Can't adjust ROF or Number of rounds to burst.
by Griffith H. on 05/16/2013
"I got the ASCU Gen 3 for my birthday. It was a gamble because I pre-ordered it and had no clue what it was going to be like. The first time I tried to install it, I installed the mosfet and all but to no avail and I gave up on it. Then I went back again and decided to put the anti-reversal latch back in and that did the charm and it ended up working. I'm very pleased with the product so far.

Great trigger response
Great ROF
Great overall product
Easy install

Instructions are difficult to understand
Not as many programs as there could be (programmable fire selector)
Selector plate is a little weird, for me, I have to place the selector in between semi and safe for it to function on semi

Great overall product. Word of advice would be to put in the anit-reversal latch, they say not to, but do it anyway.
by Glen C. on 04/02/2013
"Works great but not the easiest to install. If you install on a G&P you will need to grind out part of the gearbox. Nice that you get rid of the anti-reverse latch. One step says you need to remove the trigger spring to test the clearance. You need to install the spring with the trigger when you put the gearbox together it is not clear in the instructions. You will also need some super glue to place a small plastic block on the end of the trigger.

Don't lose it It is really small. Also I don't think a Speed trigger will work with this. It is also different than the gen 2 in that there is no contact switch other than for the cut off lever. For the life of me I don't know how the trigger actually activates the fire mechanism.

So far it works will. The three round burst is the coolest thing also no sticking semi-auto anymore.

Make sure you have a strong magnet motor or you can't use all of the features and the anti-reverse latch has to stay in. My G&P 120 works fine.

4/5 stars because it was a little more difficult than I thought and instructions could be a bit better.
by Cody F. on 09/08/2013
"I had the V2 ASCU Gen2 In a previous build and absolutely loved it. I purchased this one for my CA M4 mainly to have the 3rnd burst feature. Played 3 days worth of games and had a catastrophic meltdown with smoke and heat and a blown up lipo.... IDK what happened, but im not really impressed with how long it lasted.

Nice trigger response
Protects the motor from damage
No pesky trigger trolley or contacts to burn up

Difficult install
Didn't last long
Wires weren't really too durable
by Hugh D. on 06/11/2013
"Like my previous ASCU Gen2, this one also stopped working after a few games. I've been trying to contact Airsoft Systems but haven't gotten a response yet. It was great while it lasted but IMHO isn't worth the $100 price tag, especially now that there are other FETs coming out offering triple the features and power at the same price.

Solder-free installation
Short trigger pull
No more burnt trigger contacts

Clearly not for high power builds
Not as many options as I thought there would be
Doesn't detect some trigger pulls during rapid semi fire
The price tag (given how short it lasted and the lack of programming options)
by Andrew F. on 05/26/2016
"This thing is a piece of trash, I have gone through 3 of these things and all of them have either burnt out or had a system failure.

The first one I received, I installed perfectly. I had to sand down my gearbox a little but other than that it fix fine. But then I plug in my battery and it fired once and a tiny piece broke off.

The second I had my friend install who is a pretty good tech. He even upgraded the gearbox, new shims, shs gears, new piston, nothing in my gun was stock. I go outside to shoot it because it was good to go, and I went through about 375 rounds then it had a melt down and started shooting full auto.

The third and final one I stupidly purchased was installed by my other friend who is a mediocre tech, got it in, didn't even shoot. It just started to smoke, I was using a 9.6v battery, HOW DOES THAT EVEN HAPPEN M8. THIS THING IS DESIGNED TO TAKE 11.1 LIPOS AND IT SHORTS OUT ON A 9.6.

Never, ever, ever, ever, EVER buy this thing. It is a waste of good money. Buy a g&g ETU or the one made by ameoba because if they break it's only 50 bucks you spent and not a 100 wasted. Maybe if you have the money, just buy a BTC cuz they good as hell man. My friend has one and it is SOOOOOO sick with the ASG 28 tpa motor. Definitely buy that it is worth every penny, and not the ASCU.
by Justin R. on 05/09/2016
"After having a terrible experience with Gen1 and Gen2, I figured I would give this new Gen4 a try.

I just got it in the mail today. The installation was not great. The fit was VERY tight. After a little sanding on the large plastic cover, I got it to fit snug. I wired it all up being careful not to strip or pinch anything, plugged a 7.4 in and it fired fine three times. Then I could smell smoke and it started firing on auto by itself.

I took it out and observed that one of the mosfet had burned. Save yourself the $100 and find something else.

This is probably the worst airsoft investment I've ever had.
by Morgan S. on 11/01/2015
"My personal experience with this product was rather poor. The connectors between the two control boards broke quite soon, so I'm afraid I can't recommend this product. It's extremely poorly designed, for the price, there are many better options.

Pros of any simple mosfet system:
-Protects your trigger contacts and electrical system

Pros over simple mosfet systems:
-Marginally reduces trigger pull force
-Ensures a full piston cycle (improves trigger response and mechanical longevity)
-Three round burst if you want it
-No soldering required

-EXTREMELY fragile connectors are prone to breaking at the slightest touch
-Uses extremely stiff wire instead of wet noodle wire, making the install a pain
-Poor electrical design, many users say it burns itself out extremely soon

Really, the only core advantage of this mosfet over cheaper and simpler systems is that it gives you full piston cycles. The reduction in trigger pull isn't very perceptible, three round burst is really just a gimmick, and any good airsoft tech should be comfortable soldering.

Furthermore, the warranty service is seemingly nonexistent, as I have emailed them twice about my problems to no avail.

So, I'd advise you to stay away from this product. If you want a mosfet that gives you full piston cycles, I'd recommend one of the mosfets made by Black Talon (not offered on They have superior construction, better warranty, and are simply a better product for almost the same price. They might 10 or 20 dollars more than the ASCU, but it's well worth it.

If full piston cycle isn't important to you, then learn to solder and make your own darn mosfet. It quite literally costs 10 dollars to make one.

The point is, stay away from this POS.