STANAG AUG conversion

[Treadhead]

A while back now I was approached by a mate and asked to build a STANAG AUG. This gun was to be a true STANAG gun, capable of accepting unmodified STANAG mags. Furthermore he specified that he wanted the mags to release from the AUG’s normal mag release button – this left me scratching my head somewhat to say the least!

 

Putting the mag catch problem to one side for a while, I turned my attention to the magwell itself. Standard AUG mags are bulkier than Armalite type mags and taper towards the front, so I had to both open out the front end of the magwell and bulk out the side walls to allow the AR mag to fit in..

Many people making STANAG AUGs choose to use a modified mag and the standard AUG mag catch. This means they have to seat the mag at the rear of the magwell and modify the feed tube. I chose to do the opposite – I decided to keep the feed tube in line with the top of the mag and simply extend it to meet the mag as necessary. This meant I had to remove a fair bit of material from the front of the magwell. I made sure to save all of the shavings and filings from the black plastic of the body so I could use them later on.

 

With the position set, I could work on making the magwell fit the mag. I glued strips of a matching black plastic (in this case form a donor, scrap, AUG) onto the side walls of the magwell and when they were fully dry, sanded them back until the mag was a tight fit.

 

I pared, filed and sanded the lips of the new magwell walls back into roughly the right shape, and then got out the bottle of PlasticWeld. PlasticWeld is the brand name of a solvent called dichloromethane which is used as a plastic adhesive. It works by dissolving the material and then evaporating, leaving a solid, welded piece of plastic.

Here’s where the filings come in! I dissolved the plastic filings in PlasticWeld until I had a liquid black plastic paste, which I applied to the lips of the magwell. I very liberally used the glue and this filler material to build up a nice rounded edge and to fill any gaps.

It takes a good few hours to harden fully, but once it does, it sands and cleans up easily and looks great!

 

Once the magwell was enlarged enough to allow the mag to sit where it was needed, I turned my attention to the feed tube. As AR type mags don’t have the raised front of the AUG mags, the tube needed to be extended downwards to meet it. Ultimately I planned to turn a new, extended, part on a lathe (which I’ve since done but neglected to photograph), but I needed an interim solution. I cut the end off of a BB loading tube and fixed it in place over the stock feed tube. I then added two rails of plastic to support the front of the mag in its correct position.

 

With the mag now sitting in its proper position and engaging with the feed tube, it was time to turn my attention to the mag release. I took a metal M16 mag catch and used the magazine to find the position for the catch. Once I knew that, I could fix it in place.

The mag catch is held in place by an “n” shaped piece of plastic, which fits into a groove cut across the metal catch. The rear end of the mag catch sits on a raised block of plastic and it pivots around the forward edge of the block. There is a small spring under the front of the catch (this was glued into a shallow hole drilled into the gun body) which pushes it into the hole on the mag (or back against the support block if there’s no mag inserted). I trimmed back the corner of the mag catch to prevent it from blocking the mag. On the AR series guns, the catch moves directly away from the mag, with this design, it pivots and as there isn’t enough room for it to clear the mag completely, its corner must be trimmed. I put a plastic wedge directly above the top of the catch to prevent it being pushed upwards when a mag is inserted.

 

Then it was time to deal with the linkage between the catch and the release button. As you can see from this pic, there’s very little space for a mechanism with the gearbox trigger in place.

 

Because of this, I did away with the standard trigger mechanism altogether to make room for a release mechanism. The trigger would instead work a microswitch which runs the gearbox through a mosfet.

[Treadhead]

With some space now freed up, I was able to recycle the trigger linkages into a pair of rods which transfer the movement of the release button to the top of the mag catch arm.

 

The brass tubing on the mag catch arm is simply a spacer to hold up the pusher arm and the large gap between the top of the pusher arm and the retaining nut is deliberate. The hole at the end of the pusher arm is drilled bigger than the mag catch arm, allowing for lots of slack. As the push arm pushes on the mag catch, it rides up the mag catch arm, allowing the mag catch to pivot.

 

 

The plate directly above the linkage is to restrict the linkage’s movement and to allow it to turn the upwards motion of the mag release button into the forwards motion needed for the mag catch. Note the supports on the top side of this plate which have been cut back to allow the gearbox to fit.

 

I packed out the end of the mag release button with more plastic, to ensure that the push bar stays in the centre, and it all fits neatly together.

 

It took a bit of trial and error (and much fitting and splitting the two halves of the gun) to get everything into their final positions (mainly the mag catch itself and it’s pivot and supports) but once I did, it works fantastically.

 

 

All that remains to be done now is the trigger. My mate wanted this to be a full auto only gun with a very short trigger pull, so that made life a bit easier. The trigger has a screw fitted to the top to limit its stroke (courtesy of said mate!) and there’s a microswitch installed which is depressed when the trigger is fully pulled.

 

The switch is to be wired to the gate leads on a mosfet much like any other trigger switch (I didn’t fit the gearbox or mosfet to the finished gun as my mate had those ready to drop in, so I can’t show that I’m afraid).

 

That said, there should be no reason that, with two microswitches and a little ingenuity, a similar system shouldn’t work for both semi and full auto. Each microswitch should just have to be wired in in place of the appropriate set of trigger contacts (as the AUG box works with two sets of trigger contacts rather than one set of contacts and a selector plate). I’ll try it our sooner or later!

 

 

Anyways, with all that done, it’s just a matter of rejoining the receiver halves and doing a final tidy up to the magwell lips.

 

 

[jomarx]

Its so beautiful!!

 

I love it!!

 

[Wege]

sounds like one of the important things from this is to have a spare AUG body of the type you are about to mod.. so as to enable the plastics to be as close as possible in texture/colour?

[Treadhead]

Well it was handy, otherwise I would have just sprayed it... TBH, I only went to the trouble of doing the magwell lips like that because I had a junk AUG body lying about, otherwise it would have been car body filler and krylon...

[DFM56]

Great work mate! Time to trade my m4 for an AUG I see, the only thing I couldn't stand about them was the magazine.

any shots with 30 round mags?

[Hedganian]

That's an awesome project, very well done - now figure out how to make a drop-in kit, so that the AUG can use Steyr mags or M16 mags, as available.

[DualWieldNate]

 

Good work mate that looks spot on. As a owner of an M4 and an Aug this interests me greatly.

[Docv400]

That's a great job Treadhead, I particularly like the 'home-made' plastic paste idea.

Is it very tacky when it's in the mouldable state, and is it firm enough not to flow?

[Zatarra]

Couple of pictures with a 30 rounder please.

Is there no way you can mod a AUG so that it can accept both?

And can the real steel AUG accept STANG mags?

Thanks

[Hedganian]

All assault rifles made by NATO-member countries take STANAG mags as standard or have conversion kits available. While the G36 and AUG mags are better than the STANAG ones, they're not interchangable, so the conversion kits allow the weapons to fulfill the requirement to use standard NATO mags.

[Pkekyo-Nor]

There is actually a real steel G36 STANAG magwell converter? o.O'

[Hedganian]

Of course.

[Treadhead]

That's a great job Treadhead, I particularly like the 'home-made' plastic paste idea.

Is it very tacky when it's in the mouldable state, and is it firm enough not to flow?

 

It all depends on how much glue you use. That said though, as plastic weld is so volatile, working time is minimal, but if you're not happy, you can just wet it down with some more glue!

 

Ask and ye shall recieve:

[DFM56]

hot.

damn.

I am sooooooo doing that.

Although I have enough mags to not care about being able to use others, how do you mod the mags to work with the original catch?

[Hedganian]

If you read the thread, you don't need to mod the mags - the modified mag release ensures that off-the-shelf airsoft STANAG mags can be used.

[Squab27]

So beautiful. This would have kept me from getting rid of my AUG

[Treadhead]

If you read the thread, you don't need to mod the mags - the modified mag release ensures that off-the-shelf airsoft STANAG mags can be used.

 

Exactly - that's the whole point of the conversion...

[DFM56]

If you read the thread, you don't need to mod the mags - the modified mag release ensures that off-the-shelf airsoft STANAG mags can be used.

If you read what I said, You would know that I have enough mags and don't need to concern myslef with borrowing any in a game, so I wanted to know how easy it would be to just mod the mags to work with the original catch. 

 

 

 

[Warning]

theres two real "steel" AUG that takes STANAG mags that i know of and that's the MSAR STG-556 and the TDP AXR

 

http://www.tpdusa.com/proddetail.php?prod=Liberty_Rifle

 

http://www.defensereview.com/wp-content/up...56_AR_Mag_1.jpg

http://www.defensereview.com/wp-content/up...56_AR_Mag_2.jpg

http://www.defensereview.com/wp-content/up...56_AR_Mag_4.jpg

 

@ Threadhead, awesome mod i might have to try this mod my self at a later date if i ever summon the courage to buy and then have ago at modding a AUG

[RWJP]

If you read what I said, You would know that I have enough mags and don't need to concern myslef with borrowing any in a game, so I wanted to know how easy it would be to just mod the mags to work with the original catch.

 

And he's not gonna be able to answer that, because he hasn't done that. Judging by the work he did to the magwell, the STANAG mags are slightly longer from back to front, probably due to the bulge at the rear of the magazine. As such, the only way I could see you modifiy a STANAG mag to fit, would be to remove that entire bulged section at the rear of the magazine, and them build something at the top of it that matches an AUG mag so it will fit...

[Treadhead]

Well as Sekiryu discovered a while back, you can't have both. He modded his magwell to allow STANAG mags to fit into it and modded the mags to work with the AUG style mag catch. Unfortunately, the material removed from the magwell meant that AUG mags would no longer fit...

 

Then there's the issue of the feed tube. If you don't want to move the feed tube, then the STANAG mag has to sit very far forward in the magwell (as this one does). this leaves nearly 10mm gap between the rear of the mag and the AUG mag catch.

 

The only way you can get both is to build an external STANAG adapter on top of an AUG mag. Which would look hideous as you've essentially had to build a second magwell below the existing one...

[Kenworth W900]

I think you are still missing DFM's point here. He was just wondering how to mod his stanag magazines to be used in an AUG and use the original mag catch.

 

Putting the mag catch problem to one side for a while, I turned my attention to the magwell itself. Standard AUG mags are bulkier than Armalite type mags and taper towards the front, so I had to both open out the front end of the magwell and bulk out the side walls to allow the AR mag to fit in..

Many people making STANAG AUGs choose to use a modified mag and the standard AUG mag catch. This means they have to seat the mag at the rear of the magwell and modify the feed tube. I chose to do the opposite – I decided to keep the feed tube in line with the top of the mag and simply extend it to meet the mag as necessary. This meant I had to remove a fair bit of material from the front of the magwell. I made sure to save all of the shavings and filings from the black plastic of the body so I could use them later on.

 

He probably HAS read the thread properly and noticed the above comment (bold).

So does anyone have a link to show the projects where people have just modified their stanag magazines?

 

[Treadhead]

I think you'll find a link to one such thread in my above post...

 

Modding such a mag is the easy part, just cut a notch in the right place for the catch to engage. However you can't just put an AR mag directly into an AUG magwell as the magwell is the wrong shape (it physically won't go in unless you cut into the magwell) and the feed tube is in the wrong place....

[Hedganian]

I'm sure there's a way to convert the AUG to use both AUG mags and STANAG mags, but I have no idea how to go about doing it. Since i have no STANAG mags anyway, it's not really something that I'm all that concerned about, but it would be nice to have the option.