AA-12

[steaktipz]

Hey all, I've been wanting to make an automatic electric AA-12 for quite a while (and yes, before MW2 came out) and I've laid out a rough outline (in my head ) for it's construction. Keep in mind, this plan is far from complete or finished, it's just a rough outline of how I would get the job done. Also, any criticism or suggestions are welcome and strongly encouraged. I'm going to need all the help I can get.

 

I've laid out my plan in different tasks needed to complete the build:

Task 1: Choose/Buy a base gun

 

So far, only the former has been completed. I will be using some sort of M16, most likely from a bone yard somewhere. I chose the M16 because the stock and grip configuration look similar and it already fits a gearbox. Also, the large stock can fit a hefty sized battery.

 

Task 2: Mod the gearbox to load and shoot 3 bbs per cycle, as well as mod the barrel to have a good spread.

 

I'm planning to add two extra pins on the sector gear so that it pulls back the tappet plate and air nozzle three times before the piston is released instead of just once. I'll have to mod the tappet plate a bit, but it doesn't seem too difficult. Of course, there are probably 50 different unforseen issues that can and probably will occur, but I'll just have to give it a try. I'll be keeping the ROF low by adding a high power spring (most likely an m120) and a standard size, nothing crazy 8.4v battery. Also, I'm not expecting a ton of range out if this thing, as I've tested full sized aegs by dropping 3 bbs in the barrel, and I'd be totally fine with the range I got. (about 30-40 ft)

 

As for the inner barrel, I'm planning on keeping it hooked up to the standard m16 hop up (set all the way off) and making it extremely short, something like 4 to 5 inches or so. Once the inner barrel ends, the outer barrel (a metal tube) should take care of the rest, allowing the bbs to spread, but not so much that they spew everywhere.

 

Out of all the tasks, this seems the most daunting. Not only because I need it to work, but I need it to work reliably and not break.

 

Task 3: Modify the externals to at least look similar to the AA-12 and create a magazine

 

For the mag, I'm planning on just taking some sheet metal and making the basic shape, fit mid cap magazine internals into it, and add cutouts or protrusions in the sheet metal to make it lock into the gun.

 

As for the externals, I plan on making the rail that extends off the motor grip and runs parallel to the magazine out of metal. I'll chop out the mag well from the lower receiver and use the aforementioned rail as a guide for the magazine (like the real one). I'm not sure exactly where to put the mag release as I don't even know where it is on the real one. Once again, suggestions and knowledge are welcomed here!

 

Since the M16 receiver has a bunch of ups and downs on it and isn't smooth like the AA-12, I'd get rid of protruding parts and build up any low points with epoxy to flatten it out. I'll need to leave holes for the body pins to be punched out, and I'll need to make sure that it can disassemble, in case anything breaks. As for selector switches, I'd probably just get rid of it and keep it auto only.

 

The biggest problem I can think of right now is building the handguard. I suppose it would have to be connected to the upper receiver, and it would be built around the outer barrel. Is it possible to make the whole thing out of epoxy, or is there a better material? I'm new to the world of epoxies and custom building out of polymers, and any help would be appreciated!

 

As for the outer barrel, It would just be a metal tube attached to the M16 outer barrel close to the receiver. (the M16 outer barrel would be cut down first)

 

Instead of iron sights, I'd probably just leave the M16 rail there and get aftermarket iron sights or some kind of optic.

 

 

Like I said before, these are just rough guidelines. Also, I'm not going for a perfect AA-12 here, just pretty close.

 

So If anyone has anything to contribute, please do!

 

-Andrew

 

EDIT: Here's an (extremely laughable) mock up of how the M16 ends up looking like an AA-12 I made in MS paint. Hey, you gotta start somewhere, right?

 

[SuperKingBigNuts]

Nice job! even though it couldeve been added to the Shotgun Idea Thread,Who caresx!you just basicly made a revoulutionary airsoft shotgun design

[steaktipz]

Thanks. I hope to god that this AA-12 project works out.

[ED-SKaR]

I have some pictures of the old Automatic Atchison 12 design, that has been raped into the form of the Automatic Assault 12 of the current ilk. It is bassicaly a box fead shotgun with armilite furnature. Aparently it worked pretty good, even with paper cartrages.

 

 

 

Though i cringe every time someone tries to modify an AEG gearbox to put 3 BBs down one barrel.

 

 

 

{edit}

here we go, some older pictures on every airofters favorite website.

http://world.guns.ru/shotgun/sh29-e.htm

[steaktipz]

Hmm, although it does look like a simple build, I think that if I tried to build it it would end up looking like. . .an M16.

 

I'll stick to the modern AA-12 design, although I appreciate the help.

 

-Andrew

[Ferrarilove1]

For the magazine well you could try something like the Thompson where it has grooves that the magazine fits into.

[ED-SKaR]

Nah, if you are using an armirite body then use that magwell and stanag mags. Build a simple shell to put around the mag to make it look like a shottie mag.

[steaktipz]

I was thinking of doing the Thomson style mag well and just cut out the mag well from the M16 receiver, but It might be easier to just leave the M16 mag well and use STANAG mags. (although it would be less realistic) If I can find a simple way to make a Thompson style mag guide system, then I'll go for it.

 

-Andrew

[steaktipz]

I have also decided to find a big hunk of plastic and use that to make the hand guard, and then epoxy it to the rest of the gun. I think it would hold pretty well. . .

[ED-SKaR]

I was thinking of doing the Thomson style mag well and just cut out the mag well from the M16 receiver, but It might be easier to just leave the M16 mag well and use STANAG mags. (although it would be less realistic) If I can find a simple way to make a Thompson style mag guide system, then I'll go for it.

 

-Andrew

 

 

 

Go find the T14 shotgun. Even worse than the origonal AA12, the T14 is pretty much an M16 chambered for 12bore. And the magazines look allmost identical to STANAGs.

 

 

its not THAT unrealistic.

[Clot]

Could it be possible that a slanted feed tube be made, so that 3 bb's fed into a hop chamber of sorts?

 

I.E. Instead of one bb feeding at 90degrees, say a couple feed at 45degrees or less?

 

If you get me....

[bum_fluff]

Just to point out if you havent already gatherd, if you feed three bbs into the barrel, 2 will be pushed past the hop rubber and will no longer be held in place, and may roll down and out of the barrel, leaving one taking the full FPS of the gun which may lead to issues.

Hope you find a way of making this work, AEG shotguns are a wet dream of mine.... one day we shall perfect the idea

[steaktipz]

Just to point out if you havent already gatherd, if you feed three bbs into the barrel, 2 will be pushed past the hop rubber and will no longer be held in place, and may roll down and out of the barrel, leaving one taking the full FPS of the gun which may lead to issues.

Hope you find a way of making this work, AEG shotguns are a wet dream of mine.... one day we shall perfect the idea

 

Indeed I have pondered this problem. I plan on cutting a slit in the barrel (kind of like the window the hop up nub pushes down through, only thinner) and placing an o-ring with a smaller diameter than the bore around the barrel, so that it sits in the slit and acts as a bb retainer. The force of the air behind the bbs then overcomes the o-ring, etc.

 

Not sure if this will work perfectly; I just have to give it a shot.

 

As for the T14, that'll be my back up plan.

 

If I can't get the AA12 externals to work, then at least I'll have a functioning T14!

 

Thanks for all these different shotgun designs ED-SKaR.

[ED-SKaR]

Indeed I have pondered this problem. I plan on cutting a slit in the barrel (kind of like the window the hop up nub pushes down through, only thinner) and placing an o-ring with a smaller diameter than the bore around the barrel, so that it sits in the slit and acts as a bb retainer. The force of the air behind the bbs then overcomes the o-ring, etc.

 

Why not just rebuild the hop unit to suit your needs. Cut the usual hop slot into the barrel 12mm further forward than it normally sits, then bodge two hop rubbers together so that one seals the barrel agains the nozzle and the other acts as hop.

 

If you work from a clean barrel (IE the uncut front end of a barrel) then you should be able to make it all work without too much hassle, and if you are lucky then that might just feed 3 BBs as is, without any other modifications.

 

 

There is a common fault with hop units that causes AEGs to multifeed. I think that if you do the mod I just explained then it is possible you can invoke the "fault" to make your shotgun.

[steaktipz]

So basically I'd be making a long hop rubber that extends through the whole hop up unit? How exactly would I make the bucking dip into the new, 12mm further hop nub window? And what about the hop chamber barrel clip? Could you explain how this system would work in a little more detail?

[Kenworth W900]

AR based shotgun

[ED-SKaR]

So basically I'd be making a long hop rubber that extends through the whole hop up unit? How exactly would I make the bucking dip into the new, 12mm further hop nub window? And what about the hop chamber barrel clip? Could you explain how this system would work in a little more detail?

 

 

nonononono, dont worry about the rubbers just yet, its not that hard.

 

cutting the barrel

The barrel will need a hole for the second rubber in a position to allow 3 BBs into the breach. It is normally set up so that 1 BB gets in, so if you move it 12 mm forward, the lenght of 2 BBs then you get three.

 

I would start from the front end of the barrel and make all the cuts from scratch, rather than try to plug the origonal hole. You would need to cut the hole for the rubber and two grooves in the side to lock the barrel in place. The groves should be in the same place as the origonal ones.

 

positioning the rubbers

you would require two hop rubbers, and they wouldn't nesseserally have to touch or be joined together.

The first one is to seat against the nozzle. For this one you really only need the overhang of the rubber and then a little bit more to stop it falling off.

The second rubber would require the overhang cut off so it can slide further down the barrel, and that would be positioned over the hole.

You could cut this second rubber so it is just a square of rubber around the nobbly bit that sits in the hole. So long as there is enough rubber around it to ensure it does not fall through or move around.

 

 

You would also need to make sure that the second hop rubber does not get in the way of the groves in the barrel and the clip that goes in them, otehrwise the barrel might fall out .

Also you would have to be a little inventive with some ptfe tape to ensure that the system is fairly air tight.

 

 

 

 

Howzat?

Am I makeing any sense?

[Crimson]

you should make it so it fires 12 mini moscart rounds instead that would be total win !

 

and it would be easier make the whole thing out of wood make a strike pin system, use the preload tension system of the current moscart relolving shooter and then make a mag for it

 

that would be pure win !

[steaktipz]

@ ED-SKaR:

 

Yeah, that makes sense. I looked into it and found that a standard hop rubber is actually long enough to accommodate the extra 12mm of space between the end of the barrel and the new hop up nub hole. Correct me if I'm wrong, but basically all I need to do is cut the new hole in the barrel, cut grooves for the hop up clip, and assemble the hop up chamber like normal except for putting the nub in the new hole, right?

 

BTW, what exactly is the "flaw" that causes hop chambers to chamber more than one bb, exactly?

 

@Crimson:

 

Although that does sound like a good idea, the AA-12 is made out of metals and polymers, plus I don't have the funding for the system you described.

[ED-SKaR]

Yeah, that makes sense. I looked into it and found that a standard hop rubber is actually long enough to accommodate the extra 12mm of space between the end of the barrel and the new hop up nub hole. Correct me if I'm wrong, but basically all I need to do is cut the new hole in the barrel, cut grooves for the hop up clip, and assemble the hop up chamber like normal except for putting the nub in the new hole, right?

 

BTW, what exactly is the "flaw" that causes hop chambers to chamber more than one bb, exactly?

 

 

You're forgetting one important thing. The hop rubber has a bulge shaped part that fits into the hole, you would need to use this part in the new hole. Its in the wrong place on the hop rubber to make it work with a single unmodified rubber. You'd need half of it to seal against the nozzle and the other half with this bulge to go into the hole. I'd recomend using two hop rubbers so you can have more rubber to seal around the gaps.

 

You should be able to find a couple of TM or chineese rubbers that people don't want, you dont need good quality rubbers... its a shotgun after all .

 

 

 

The usual flaw with the hop on normal AEGs is that the BBs want to push down the barrel when the nozzle is in its rear position, and the hop rubber (the bulgy bit) stops them. However when its not set up right or the rubber is worn or damaged then it can let BBs slip past it, letting more than one BB into the barrel.

 

I think this is the case... It might be the lip around the breach that stops the BBs moving foreward, that would require a little extra work to "sabotage" the lip, as well as moving the hop foreward 12mm.

 

 

 

 

@crimson

Do you have any idea of the scale of difficulty in what you have sujested, and beyond that the cost. After all that, the practicality of using that.

 

You would have to stop every 12 shots to reload all your moscarts. That dosen't sound like a gun you can scirmish with to me.

[hitmanNo2]

But it would be unbelievably epic though.

[ED-SKaR]

But it would be unbelievably pointless.

 

 

 

You people don't understand what a shotgun is, and what a shotgun should be. Thats fine and all, but leave this thread to the discussion at hand please.

[hitmanNo2]

Eh? That is not in question. I'm sure we all know what a shotgun is. I don't quite get what you're getting at. You cannot deny a drum fed, mini moscart powered AA-12 would be less of a shotgun than an AEG firing in 3 round bursts essentially.

 

But anyway, this sounds like an interesting project and I will be keeping my eye on it

[ED-SKaR]

I ment there is a certain mentality to shotgunning. Just like there is a different mentality to support gunning and marksmaning*.

 

Shotgunning is NOT just spamming a few shots and knocking off for lunch. Thats how you'd play with 12 minimoscarts.

 

Yes it would be a "shotgun" a gun that shoots multiple projectiles, but shotgunning is more than that.

 

 

*is that even a word...

 

 

 

 

{I'll shut up before i make shotgunning look like a religion }

[steaktipz]

SO ANYWAYS, I'm planning on ordering a JG M16 from the boneyard on Airsoft Megastore today for $70, and as soon as it arrives, I'll get working on the 3 bb loading system.