It's Almost Like The Part I Wanted

A couple of weeks ago I ordered some longer accessory rails for the G36C. I only would have needed one, because I was planning on putting it on the bottom of the handguard, but they would only sell packs of two, meant for the sides.

The default rail feels a bit short in my opinion, so with a longer rail I could have the foregrip a bit closer to my body.

Original grip placement on the default rail

Enthusiastically, I opened the bag of new rails, removed the foregrip and unscrewed the default rail. I began fitting the new rail only to notice it wasn't actually up to spec.

With the front screw hole aligned, the rear one doesn't come even close.

I'm sure you can imagine my disappointment at this point. I had waited for these things to arrive for more than two weeks, and even though they were sold as G36C accessories, they do not fit it. And no, the side rails do not have a different screw placement, so every rail should be able to sit anywhere. Not these things, though. 

After some searching I find the specs for the real steel G36C, and after comparing them to my airsoft gun, I see that the replica is well copied from the original, whereas the rails I got are simply not correctly made. A replacement would take forever to get here, so I just decide to fix this situation myself.

The front screw hole seems like the obvious place to work on this piece, since it's already an oval shape and there's only little material nor is there any actual rail in the way. 

With the rotary tool, I first try a grinding bit with similar dimensions as the hole, with the idea of simply grinding away enough material so that the screw would go through. The grinding tip is too fine, though, so this takes ages. 

I quickly get bored with the lack of progress, and switch over to a cutting bit. I can't use that one from the inside out, though, so the whole front of the hole has to go. The rotary tool is definitely great for this kind of work, since it's light and easy to manoeuvre around. With the cutting tip I can both cut and grind, so in a few minutes I have a nice, clean looking result.

I screw it on, but it's almost as if someone keeps going "Not so fast" all the damn time. Not only is the rail too short, it's also a too thin: Having screwed the rail and the front sling point on, I notice there's a bit of up and down wobble. So off come the screws again and I'm back at the planning stage.

Luckily, it doesn't take long to come up with a solution. I have it handily lying around, and it worked for the AUG, so why would it now work here? So duct tape, the sticky but ever-faithful hound of the handyman, to the rescue!

It sure is thicker now!

Stuffing this thing back into the sling mount isn't easy, but once done and the screws are tightened, it definitely doesn't budge.

I fiddle around a bit with the foregrip to find the perfect placement, and it indeed feels most ergonomic a few centimetres further back from where it used to be. It was all worth it, in the end!

Here we are. It's all better now!

Teething Problems

Today the long-awaited steel spring guide arrived, so I got to open up the AUG gearbox. Again.

Some violence and swear words later (I only had to reopen the box once because the trigger return spring got out of its hole), I actually had, on the table, a real-life closed gearbox with an M135 spring, steel spring guide, aluminium piston and piston head, and an o-ring nozzle in there.

Now I would just need to see if the default motor was strong enough to wind the whole thing. Since the MOSFET setup didn't really work after attempts one and two, I've decided to look into it later, and thus soldered the wires back to their original places.

I plugged in the battery and hesitantly pulled the trigger: The motor gave a short whine, the piston moved maybe a centimetre backwards, and then everything fell silent. Pulling the trigger didn't do anything anymore.

After some troubleshooting I looked at the fuse and it was very obviously blown. At first I just thought that the motor had too little power to pull the heavier spring, but decided to open the gearbox (again) to see if something else is wrong. Maybe the piston was still getting stuck to the sides.

And it truly was, but not the way I thought. I had shimmed the gearbox a bit wrong. The sector gear was riding a bit too high, and the piston had a lip overhanging the rack. What happened was the sector gear dug into the piston and the fuse naturally blew once the tension got too high.

You can see the dents where the sector gear teeth have dug into the piston body

So now I'm going to need some new fuses. And I've just ordered a high torque motor, just to be sure. The gearbox shall now wait until I get everything, I just don't have the energy to start mucking about with the trigger right now.

Carrying Capacity

About a month ago I bought a Molle Carrier vest with which to replace the rather poorly functioning Bundeswehr harness I had been using so far. As with any Molle base, you can slap on all sorts of things that fit the standard, and that is exactly what I have done. At the moment I'm quite happy with the layout, since I can carry all I need and more, and the vest fits way better than the harness ever did.

Small utility pouch, radio pouch and triple mag pouch do the trick on the front

Dump pouch and large utility pouch on the back

Why is he blabbering on about his stupid vest you ask? Well, it was supposed to be game day tomorrow, but I just found out that it's again cancelled. Since I now have free time on my hands, and no reason to be up early tomorrow, I decided to cracked open a couple of beers and that's when it hit me.

What is the functional beverage carrying capacity of my current gear? I have no clue! There is no piece of information more important than this in the world at this moment. Being the curious sort, I just had to figure this out, and without further ado, here we go:

Saku is a nice lager style beer from our neighbouring Estonia

Starting with the obvious, the mag pouches, we are already carrying six

Radio? I don't need a radio, I can just mumble to myself

The radio pouch and the small utility pouch can only take two each

Turning the vest around, the large utility pouch can suck in up to seven cans!

Finally, the dump pouch (it's not cheating, damnit!) also takes seven

And here we are. It's still wearable!

Final tally: 

24 four cans of dynamically tasty tacticalness with which to achieve situational inebriation. Total weight is 11 kg, so I might not be running far, but at least I can always have a drink when I'm thirsty. And I'm feeling a bit thirsty right about now.

Rebuilding a MOSFET

I already tried my hand at building a MOSFET for the AUG, but it didn't quite go to plan. Today I decided to retry. This time I didn't burn it up when building, so I put the gearbox back in the AUG and did some test shooting at home.

I got a whopping hundred-or-so shots out and then the MOSFET shorted again. Lovely. A full-auto AUG without any controls. Nothing left to do but disconnect the battery and throw everything back in the closet. One of these days it will work, damnit.

Get a MOSFET They Said

I have come to the conclusion that getting a MOSFET for the AUG is a good idea. That should spare the trigger contacts and make for a crisper trigger response. Sounds like a pretty good deal to me. I know there are ready made MOSFETs around, but I'd rather save some money, get the parts myself and try my hand at building one.

Now, I will readily admit that I'm not an electronics wizard by any measure. However, I can follow guides quite well, and have built other stuff in the past with success. After finding a promising looking how-to, I bought the parts and started soldering.

I could only get resistors in packs of 50, but at least they cost next to nothing. I got more than one of the MOSFETs as well in case something should go wrong

The AUG gearbox is handy in that you don't need to take it apart to be able to put a MOSFET on, since the wires are soldered onto the outside. This is apparently done to achieve the two-stage trigger mechanism. This thread on airsoftforum.com pretty much describes the process of installing the MOSFET.

As I started desoldering the wires, I found it was not quite as easy as I thought. I have an adjustable power soldering iron, but even at full blast it took ages to make the solder on the gearbox melt, and as soon as the heat was taken off, it would set again. What is in that stuff I don't want to know. In the end I was however able to suck off all the solder and wire in the MOSFET.

I have to admit it took me a bit of time to actually make sense of the wiring diagram, since the positive and negative marked wires didn't seem to make any sense. I have the default, small Tamiya connectors on all my batteries, and I went to Wikipedia to see and make sure I got them the right way around. Ok, positive is the square terminal, negative the other. Would not want to have my motor turning the wrong way, definitely.

Comparing the diagram and the connector didn't seem to make any sense though. The fuse seemed to be on the wrong wire on the diagram. I started to feel like I'm just dumb for not figuring this out, until about fifteen minutes had gone by and I went on Wikipedia again and read a few lines further, where it says "In some cases, Mini-Tamiya connectors are wired in reverse polarity. This is often the case with airsoft guns, where the square profile terminal is the negative terminal and the rounded terminal is the positive terminal." Right. Great. Why? I don't know the reasoning behind this non-standard wiring but at least I'm wiser now. Time well spent.

With the wiring issue sorted, I finished up my soldering. I hooked up the battery to see if everything works, and with building anticipation pulled the trigger. Everything worked! Brilliant. I'm not dumb after all!

My elation was rather short-lived though, as I apparently managed to touch the MOSFET on the soldered wires, thus shorting it, and with a bit of smoke rising towards the roof, the MOSFET burned up internally so that the circuit was now eternally closed, and the gearbox was running on full auto regardless of whether the trigger was pulled at all. I guess it's a good thing I bought spares. I took off the battery, boxed up the pieces and went to bed.