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Custom AEG help.

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Hello Airsofters.

I'm having some troubles with my AEG. It's a custom made v.2 AEG made with all SHS parts, the gears are 13:1, and an SHS HT motor. The setup is running on a 11.1v lipo 25-50c discharge battery. The gun does have a mosfet that is homemade.

The problem with the gun is that it locks up in the middle of a cycle when i pull the trigger fast. I have no problems unlocking it by swapping to full auto. The gun shoots fine on full auto and when i don't pull the trigger too fast. I tried adjusting my motor, but it did nothing.

Any ideas to what I can do would be greatly appreciated!

Thanks in Advance

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That is a design problem with the V2. You have to do full trigger pulls every time. That's something we all had to learn.

The only way to fix that is to install a programmable "mosfet" (it is a microcontroller with sensors and a mosfet actually) that completes the cycle fully even if you release the trigger too early.

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You do understand that that spec is a 40rps build

13:1, shs torque, fet + deans & a whopping 11.1v lipo


With that in mind you must have a bloomin' quick trigger finger

to release it that bit too quickly and leave it stuck it dead zone

If you leave it pulled for a split second she should fire very nicely

but at 40rps you gotta be just flicking that trigger

if she is working correctly at that speed without the flick of the trigger

then it is just you being too hasty on the release of trigger


if you ain't hitting at least 35rps something ain't right

but even at that speed you had best done your homework to avoid PE

(Short Stroke & m115+ spring)


if you proceed running a build like that on 11.1v on stock m100-ish spring......



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Not on a stock spring using an m120 spring. Piston is not short stroked afaik.

But yea i guess im just releasing the trigger a little too fast. Guess another mosfet is the next thing to upgrade!

I don't even fire the gun in full auto when in game, since i play at a semi only site.

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Ahhh - dmr or a pdw size gun ???

(all the same think a pdw 110-140mm barrel would still be a tad hot on a m120 unless you losing fps somewhere)

though some sites allow up to 370fps I think I've seen on aeg's


anyway no matter - there are a few like in the Gate range of fet's

also Kong II or Kong 3 burst mosfets @ Airsoftworld or at a push Zero One also stock them

a bit of a headache getting ya head round them at first but can add bells n whistles 1-2-3-4-5 rnd burst

all with or without the one touch flick option...

Will take a little configuring and on higher rof guns it will be different to program as opposed to stock rof guns

but worth a look....


or go nutz down the BTC route

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It's just a regular m4 pretty much, its in king arms m&p15 atm. Barrel is 230mm. the gun gets around 420fps wich is the limit at the field i usually go to :).

i have been thinking of downgrading to an m115 or m110 since i dont need that much fps.

Gates are easy to get where i live so im liking the look of those.

thanks alot for the help!

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if its 420fps on a 230mm barrel then my hunch is its a bit over a proper m120 tbh

(should be on the 400max maybe 390 on a 230 say 390fps - spring ratings do vary a lot)

plus add in a bearing spring guide + piston bearing = 2 x 5mm extra spring compression increasing fps

though tbh piston bearing is not what I use as it adds weight and comes undone unless you use threadlock

(bearing spring guide & drop piston bearing is fine - recommended for higher rof setups)

soz but just pointing it out as each of them bearings can add 15-20 fps each due to compressing spring more


Gate's are nearly all AB's once you get into the mid range - though think one or two of them can turned on/off


Be careful if dropping spring down too low in case you get close to PE

tbh - what you could do is short stroke it a couple of teeth

roughly speaking each tooth will drop ABOUT - I say about coz its hard to calculate exactly.....


each tooth could reduce fps by "about" 15fps or 6%-ish (multiply fps by 0.94 for each tooth)

SS a couple of teeth could drop say 30fps and help to avoid PE


As long as she fires properly in semi if trigger held down = then the trigger switch is working correctly

Some v2 switches need the selector plate's copper strip to make full contact on them 2 prongs behind switch

others like shs - have these contacts bridged so selector plate's copper strip isn't needed

others like G&P - maybe D-Boys don't have these prongs at back of switch at all...


Just saying if on semi she spluttered to fire these contacts "could" be not making proper contact 101%

but if she fires correctly by holding down the trigger a tiny bit longer then that rules that out

and yes it is you releasing trigger that tiny bit too early - leaving the cut off lever slightly raised in the dead zone


see how you go - Kong ain't bad - not tried Gate mosfets but plenty have them

or just retrain your itchy trigger finger


SS though might be a wise consideration rather that drop in a too low spring and get overspin or PE trouble

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