AUG semi auto problems

[tunabreath]

I looked around but couldn't find anything pertinent. I did read on a review that the AUG's semi auto reliability was questionable compared to guns without the two stage trigger (pretty much all others...). This is my first AEG and my first time setting up and operating an AEG myself.

Anyways the problem is that I cannot fire the gun in semi unless I pull the trigger excruciatingly slowly. Even then, every second shot doesn't cycle the gearbox (I can hear the motor make a brief clicky run, but nothing afterwards).
I have a feeling that this has nothing to do with the trigger mechanism but is actually a battery problem. It closely resembles my full auto modified EBB running on low batteries (runs fine on full auto but cycles slowly on semi).

I think I'm charging the batteries incorrectly. Everything is stock, so I have a 8.4V 600mAh NiCd mini. I'm using a Super Brain 959 charger which i used on RC planes, charging on lowest output for safety (I'm also unsure of what settings I should be using. Currently, charging at 0.5A, 5mV). It seems to charge unrealisticly quickly, leaving the battery at 9.xV and fairly hot.

I don't really know what to do. Is this just a first time battery run through problem? Any help would be appreciated.

[mcguyver]

I also use a 959 and I have an AUG. I use a 9.6v custom battery for it and I charge my battery at 3.0A and the peak sets up automatically at 25mV. The trigger and semi firing are fussy and sometimes the gun will "dry fire" 1 round and fire on the second pull. I realize that sometimes a guy might want to use semi-auto, but in airsoft most work gets done in full-auto unless you have a super-accurate big velocity sniper rifle like Blatyman's M-14's. The battery you're using is too small for this gun and I've found that a 9.6V 1100mAH battery is just right for a stock AUG. I tried an 8.4v 1100mAH battery initially, but found the R.O.F. at 10rnds/sec. to be too low for my tastes. A 9.6v picks it up to 13rnds./sec. where it should be IMHO. You should try a larger battery to ensure good play time and R.O.F. I have it on very good authority from a previous real AUG owner that the real one takes some getting used to as well.

[tunabreath]

update, battery seems fine, the problem is in the trigger. It seems that the trigger rests further back than the connection point is for semi. If i try really hard, I can get 9 out of 10 shots to fire in semi, but again, I have to pull quite slowly. Is there any kind of fix, or should I just get used to it? I'll probably work on getting a bigger battery in there as well.

[mcguyver]

I've only run across maybe 3 or 4 AUGs and they were all that way from what I remember.

[gandar]

There is a mod kicking around on this site that shows how to cut the fire selector so you can get a semi-auto selection that will actually not allow the trigger to be pulled back further than the semi-auto length. Just do a search for it, I don't feel like looking right now. But I remember seeing it.

[tunabreath]

Ok, all battery issues solved, however the semi auto problem remains.

It seems to have gotten worse and worse since I got the gun. Semi auto hardly ever functions at all now, and I'm, getting a weird metalic springy clicky sound when I half pull. I'm only worried because this makes it very very difficult to make sure that the spring is decompressed for storage.

The only modification I've done to the gun was to place the fuse box behind the back plate (per McGuyver in another AUG related thread) in anticipation of fitting a larger battery, though I can't see how this would affect semiauto function.

Any solutions? Also, (this may have been asked before) how long can I leave the gun without knowing what state of compression the spring is in before the gun starts to suffer?

[mcguyver]

Turn your AUG upside down and look in the feed nozzle (may require a flashlight). You should see the nozzle where it enters the hop chamber. If you fire a short burst in full auto and see the nozzle fully engaged in the hop chamber, then stop there. Your spring will be about as decompressed as can be expected without semi capability. If you don't see it fully engaged, or you see it partially in the feeder, repeat full bursts until you do see it engaged.

If you use the gun regularly (like weekly), I wouldn't bother with trying to keep the spring decompressed. But if you only use the gun once in a while, then yeah, do it.

This work for pretty much all aegs regardless of brand or model, with probably a few exceptions or specialized guns.

Like i said previously, semi is fussy, even on my AUG and I bet that I don't have 5000 rounds through it in 2 years.

[tunabreath]

FIXED! After all this time, I've finally taken the time to look over the techincal guides on arnies and remove the gearbox from my AUG. After that, diagnosing the problem was easy as pie.

The funny clicking noise was the semi-trigger sear failing to fully engage the free moving part of the semi auto switch. This was due to two problems: the free moving part of the switch was worn down on the front (where it meets a spring loaded piece that keeps it in contact with all the parts around it), and the spring on the aforementioned piece was too weak.

My solution was more of a jury-rig than a true fix. I glued a small allen wrench on the side of the mechbox that holds the spring piece in the proper position to maintain contact, and hooked an elastic around some of the pegs to aid the spring. It works pretty well flawlessly now, but I'm not entirely sure how long it will last.

[tunabreath]

Or not...

Haha, It's really sticky sometimes, but it does work. Also, I found the secret to the semi-auto burst function in the AUG. Depending on how hard that spring is, it may take several strikes by the semi-auto cutoff lever to disengage the switch, so in effect, gives regular multiple shots on semi.

The stickiness isn't really due to the fix itself though. It's a combination of wear on the rear side of the free moving part (where it contacts the trigger sear) and a piece that I tried to glue in as an earlier fix attempt (on the inside, it left some glue residue that's causing some roughness in the semi portion of the switch).

Update:
I just successfully took apart and reassembled my gearbox to clean up inside. I had to remove my fix to do it, but the trigger is smooth again. Aaaand now I'm too tired to apply the fix again...

Update again:
Ok, I've applied the fix with a toothpick this time (easier to adjust due to the tapered end). It works very well outside of the gun, but once in the gun, after about 20 shots the trigger slips out of its notch on the semi bit and won't re-engage. Also, working the semi constantly seems to have worn the part further to the point where it has a hard time connecting at all. I'm not really sure how I can fix this...

[tunabreath]

Final fix

Everything works perfectly. Apparently my first fix bungled up the mechbox, so I repaired all of it and cleaned it up. Fixing the semi auto was as easy as scoring the semi auto switch with a dental scrape, deepening the notch where the trigger catches the switch. From my previous work, the trigger spring was seriously weakened, causing the trigger to lock back after firing. I fixed that with an elastic band .

Wow. Semi is awesome. I never actually knew how accurate my AUG was until now. Before, firing only in full auto, I got around 15cm groups at 10m. Now I get less than 2 inches, often getting same-hole shots.