Mini, regulated, cheap air supply?

[lozz08]

I am going to make a handgun semi-auto pneumatic, I wont go into the design, but I have this problem... I need a supply of air built into each magazine that will give me 200PSI for 12 shots. Chamber volume is about 2cm cubed, so I need 24 cm volume of 200 PSI air. But I dont know how to make a regulated air supply or anything.

[jackssmirkingrevenge]

Mini, regulated, cheap air supply?

I don't think you can make a coherent sentence with those words. If it's going to be mini and regulated, it's not going to be cheap.

If you're on a tight budget something like this will have to do. Just one of these hooked up to your launcher and the magazines just for ammunition.

[grock]

you could try modding a crossman c11 (airsoft gun) you can find those at walmart for about $35. they shoot .2g bbs at about 550 fps when new, and settle to about 400 later.

[lozz08]

Australia, otherwise I'd just buy bb guns but I have to make em.

[jackssmirkingrevenge]

The bottle I suggested above hooked up to a blowgun and magazine setup will probably give you enough semi-auto shots for an average skirmish without needing to be refilled.

You could go even simpler and make a BBMG like this one.

[tghhs]

Australia, otherwise I'd just buy bb guns but I have to make em.

Cool man, another AUS spudder, where do you get your bb's?

[lozz08]

Well, theres a place called outdoor wharehouse based in brizzy that ship 0.12g and steel bb's, problem is they're both bad weights to be using for airsoft purposes, but I think I can live with 0.12g for now. Gonna try order some 0.25g from china and say its slingshot ammo (loophole).

[lozz08]

The epoxy gun is cool, the piston design is great, I think I might use that. One Question, how does a regulated air supply work without a compressor? I know CO2 tanks give off a steady pressure because its going from liquid to gas, but can you have just a normal air tank thats regulated?

[POLAND_SPUD]

what about unregged propane ??

can you have just a normal air tank thats regulated

yes.. that's how HPA setups work

[lozz08]

Lets say I calculated that I have a certain amount of space in my mini tank, and I know that each shot takes a certain volume of air at a certain pressure. Lets say I calculate what pressure I need to fill my mini tank to, in order for it to be able to supply enough air for 12 shots. Is there a valve I can stick in my gun that will, when opened, only allow a certain amount of air in and then immediately close? thats really what I'm looking for here.

[jackssmirkingrevenge]

What is your tank going to be made of, what facilities do you have to fill it?

If you're a bit creative with materials you can make a hammer valve, like a blowgun but instead of actuating it manually you strike it with a hammer so it only opens for a brief period. There are devices containing ready made hammer mechanisms like cap pistols or automatic staples.





You might also want to look at Antonio's designs like the P2 and P3, ingenious use of commonly available materials without the use of sophisticated tools.

[lozz08]

Ok, I think I'm gonna go with a co2 semi-auto. My main concern is economy because I dont wanna be buying heaps of little co2 cartriges (using 16g threaded cartriges) These guns I'm making will be for close quarters only, so I only need a joule of energy, and I'm gonna use 0.12g bb's. What I'm really concerned about is making the same amount of gas come out each shot, but in a small package (handgun) And keeping it semi-auto. Got any tips for me?

[jackssmirkingrevenge]

If you're willing to put the effort into making a hammer valve of which I already gave plenty of examples, then a 16 gram CO₂ cartridge will give you a lot more than 12 shots.

Alternatively you can hook up a tyre inflator directly to a magazine like this little thing and fire short bursts only, it will be semi-autosih with a lot less effort.

[lozz08]

hammer valve sounds good. Could you point me to some of your threads on it?

[jackssmirkingrevenge]

hammer valve sounds good. Could you point me to some of your threads on it?

As mentioned before the best (in terms of ease of manufacture with basic materials and facilities) I've seen on this forum are Ant's designs.



If you want to use CO₂ cartridges, my best advice would be to get your hands on one of these - not too expensive - and then create a mechanism which strikes the trigger. You can either make this from scratch or find some sort of toy revolver with a working hammer that can do this for you.

You can then hook it up to a barrel and a simple tee magazine as I used here.



This way you will get much more than 12 shots. Typical CO ₂ pistols (with significantly more than 1 joule of energy - therefore using more gas per shot) will give 80 or so shots from a single 12 gram cartridge, you will have a weaker hammer so use less gas. This way it would be ideal to have a fixed magazine on your launcher.