AT4...

[HardDog]

I'm a new guy here, and luckily I found this place trying to find build plans for my AT4. I've been searching relentlessly trying to find plans/ideas to get my De-Milled AT4 into a Nerf Pocket Vortex launcher. I've seen pictures and videos of some completed builds, but no one was offering any tips/ideas/builds with it. I've started reading through the posts on here trying to figure stuff out.

Basically what I'm looking for, is ideas or plans to build a pneumatic operated spud gun that will fit inside of a de-milled AT4. Here is a picture of one of the builds that I found that I was interested in trying to figure out (he says is pneumatic-actuated piston design):

I'm looking to either power it by a 12g CO2 Cartridge or compressed air.

As for the cost of the build, I'm not really limited for money. I'd like to build it for under $200 if I could. Any help would be greatly appreciated!

Thanks

[FishBoy]

ummm... your pic doesn't work


edit- o btw, this will most likely cost you around $100 (probably less)
also your pic still doesn't work

[Davidvaini]

that perticular AT4 is a piston, look up info on how to make a piston.

[Hotwired]

The picture does work, you may need to right click and hit "View Image" or "Show Image" before it works properly on the page.

Nerfs aren't that fat, you could make a coaxial launcher and stuff it in there.

[HardDog]

If you can't see the picture, here is the website of article where I found the picture: http://www.arniesairsoft.co.uk/?filnavn ... custom.htm

So, it is a piston design. I just want to make sure my understanding of the piston design is correct; you hook up an air source, the air slides the piston forward, creating a seal around the barrel. The air then fills the chamber, when the air source is released, the piston slides back and all the air escapes through the barrel, pushing (shooting) whatever was in the barrel out.

As to the coaxial design, I'm going to need to read up on that some more to get a full understanding.

[HardDog]

Ok, so I read up on the Coaxial design and got a pretty good understanding on it. I believe I'm going to go with that design...as it seems like it will work fairly well with what I'm trying to do. First, I need to measure the inside diameter of the AT4 to get the exact measurement...I know it fires a 84mm projectile, but I need to see what the biggest size of pipe I can use for the chamber.

I do have one more question right now and I think once I get that answered, I should be able to start pricing out stuff. In the piston design, when the air is released, that's just the air behind the piston, correct? And that slides the piston back, allowing the air to escape through the barrel. Now, would it work if I could rig up something to strike the middle of a valve (like a tire valve) and allow that air to escape, it should send the piston backwards and thus carry on with the normal operation? Sorry for the long questions/explanations, but I'm trying to get this figured out before I go and try to build this up.

[Hotwired]

Yes, looks like you've got the idea of how a piston valve works.

I guess you could rig up something to hit a schrader valve but if you're talking about using the biggest pipe possible to stuff in there then a schrader is likely to be very undersized for a pilot valve.

If you wanted it to be as realistic as possible you could see if you could put an electronically actuated sprinkler valve in the back to pilot it and get the wiring, batteries and switches fitted into the AT4 body.

It may need to be offset from the centre but if this isn't to be a high pressure launcher there shouldn't be any problems is making offset-from-centre holes.

Another hole for a fill valve will be needed too, maybe connected to tubing or small diameter pipe to poke out past the sprinkler.

[glompos21]

Can you post detail pictures of the de-milled AT-4??

[HardDog]

Can you post detail pictures of the de-milled AT-4??

I'll be able to get some, but not right now. I'm a Marine that stays on base and I have the AT4 at a buddies house, I plan on going out to his house tomorrow and when I do, I'll get some pictures.

[martyr_maker]

I wish you luck. Im working on a demilled m72 with coax internals right now but its been kicking my ass for the last couple months.

[HardDog]

I've got a good idea of what I want to do, I just need to get the exact measurements of the AT4, so I know what size to make everything. I'll have pictures of it while I'm working on it, and hopefully everything will go smooth...I should be able to squeeze that Sprinkler Valve into the back area if I shorten my chamber up, and then wire it to the trigger (hopefullly). I know the one I have still works correctly, I just haven't really looked at it in depth yet. Time to go start pricing some stuff...

[Mr.Sandman]

you could also do what this one guy on instructables did and put one of those co2 airsoft m203 shells and you'd be all set because all you would have to do is charge the back with green gas and press the button in the back and it will fire. included here is a link to the instructable and a pic of an airsoft m203 shell


M203 shell:
http://www.kapowwe.com/Merchant2/mercha ... ore_Code=R


And the instructable:
http://www.instructables.com/id/Airsoft ... -launcher/