Outlaw's Build Thread

First project, I'm checking out a Tokyo Marui AUG for a friend. He dropped off the box months ago and whatever is in the box is what I have.


This is my first time working on an AUG (almost my first time on anything non M4 or AK) but I have a fair bit of gearbox experience and Google at my disposal.

It wasn't in terrible shape, but had a broken foregrip, missing butt plate, missing gearbox reinforcement plate and tiny retention plate for the takedown pin. Here is a diagram I found and I circled the missing parts:


I also tracked down sources for these parts, all except the retention plate.

The foregrip and butt plate:


And the gearbox reinforcement plate:

The gun is currently in functioning order, but you have to be carefull that the takedown pin doesn't pop out and let the barrel assembly slide out. A quick chrono and range/constancy test gives me 295 FPS and 15 RPS. This was with a crappy 8.4v NiMH battery, I could probably get it up to 18 or 20 with a 9.6 or 7.4.

I had to use tracers (it was like 8:30) and my Acetech unit which gave the AUG a bit of an interesting look.


If I ever own an AUG I'd get a smaller tracer for sure.

I'm in contact with the owner about whether he wants the "aesthetic" parts I linked earlier, and will report back when I hear.

Update:

So I worked on my M14 this week, and I officially hate teching that platform. So many random bars and springs. The first time I messed with it I watched an instructional video, but this time I decided I didn't need it. I got it, but had to tear it down again several times because I forgot bolts and springs and things.

Issues: the aftermarket wiring harness and mosfet the previous owner had installed didn't fit very well causing it to pinch wires sometimes during reassembly. Not an issue when finished and tested, but scary and annoying (raise your hand if you plug a battery in while your freshly teched AEG is unloaded cause reasons).

I had previously swapped the motor and spring (the motor was broken), and the gun since then had developed a double firing problem. It may have had something to do with the fact that the Tienly 45k is a STRONG HS motor, apparently capable of overspinning an M140.

Solution: I tore it down, cleaned, reshimmed and relubed the gearbox, fixed the original motor (I swapped plates with a random stock motor), rewired the whole thing, and sewed it all back up.

I believe I installed the AR latch incorrectly because it still double fires, but the second shot is very weak and inconsistent, indicating that everything is overspinning slighty and sliding back to the "at rest" position.

I need to get a new slow motor and make sure the AR latch is working. What should I get? I'm leaning towards an Acturus 20k. Thoughts?

Setup is;

Arcturus 19T 28K motor

Lonex Gearbox Shell

Stock Lonex bearings

SHS 12:1 gears (I was mistaken when I said 13:1)

Perun optical. No AB no precocking.

M120 equivalent—shoots 380 w/ .20

Turnigy Nanotech battery: 5000 Mah, 60-120C, wired to deans ultra

SHS piston w/ POM head. Weight is 20g.

Sta lube disk brake grease, applied conservatively to gears, piston rails, etc.


Before you report to R&D, you should know that there may be tolerance issues causing inefficient shimming, which may have contributed to the extra heat. Even with no shims in the gearbox, the gears will not cycle more than twice on a shim test. They have the exact same results shimmed. I haven’t had a good chance to mess with figuring out the gears.

With the fully charged 11.1v I got 31-32 RPS at last chrono, but I‘m fairly certain that the motor actually got hot enough to demagnetize and lose torque, as the trigger response has inexplicably worsened dramatically since the day I cooked my hand. (I can post vids of before and after) The battery and wiring was also cool to the touch, even after fairly cooking my motor grip.

On another note, I spent the day today running a bone stock Arcturus Sword Mod with the 21T 24K motor, and it also got warm on persistent semi auto. Not warm enough to cause me to suspect any issue, I just didn’t expect a 24K motor + 18:1 gears to heat up any… battery and battery wires were both cool to the touch.

I’m assuming your primary is an M4?

I’ve been looking at the “really quiet M4” problem as well, and here’s what I’ve come up with:

I’m working on making an extra quiet SR-25, so basically the same principles.

Lonex Spiral bevel and pinion.

Full cylinder, paired with 509mm barrel (right for SR-25, more like 380–400 for reg cylinder.

Silicone CH buffer mod. This is quite a bit quieter than sorbo in my experience. I’ll see if I have a vid with a gun using this mod.

Mix and match gears for best meshing. I think for this SR-25 I’ll be using the A&K sector, lonex bevel, and then an SRC 22:1 spur.

Noice motor: Tienly 35K for me, newly cleaned out, and greased the tower bearings with ceramic bearing grease. Some people say brushless, but I actually think brushless sound signature is louder in practice. They’re a heck of a lot quieter, but the one I’ve dealt with is higher pitched than the Tienly, so it comes through the grip more.

You can use precocking as well, but using precocking bothers me for some reason.

I was also going to try and fill the buffer tube with foam, as I notice that my replicas are louder with the stocks off, so some foam should help deaden it.



Foam suppressors can put in some work if you’re not perfectly volume matched. I’ll see if I can upload a video of my own primary with and without the foam suppressor I put together.