So.....im finally making an air rifle. I have a few parts already, but the only bits im probably gonna have trouble with is the air supply(gas/co2 or whatever) and a way to connect it to my valve. Anyone in aus know where i could get a decent air store or should i just use the pvc(or abs) tube for a pressure chamber like in a pneumatic spud gun? So far everything is working much better then i expected. The barrel joined to the push switch with a piece of copper elbow(you know what i mean....). So far the whole build has cost me $5, $5 for the barrel(19mm aluminium tube). The rest was liberated from my old work(hehe) and from bunnings.

Any advice is appreciated.

http://i38.tinypic.com/2u61wf8.jpg
Pic of The completed(almost) trigger assembly. 19mm O.D Aluminium Tube, joined to a 20mm O.D Steel threaded thingy by a 20mm copper thingy.

Can u braze/solder/whatever it's called these 3 things together?

If it doesnt belong here feel free to move :P

Look up BB machine gun, try xinventions.com etc. Can't link you, at college.

i wouldnt call a 19mm smoothbore to be an "air rifle", but whatever.
it all depends on how you want it to perform. this is determined by desired pressure and stuff like that. a basic design would be that of a spudgun, just scaled down. if youre going to use an air compressor, i would really recommend you not using PVC as a chamber unless you have a pressure guage attached to it. if you are hand pumping it, PVC is fine.

as for joining silver soldering them together would work, but im not sure about the aluminium. though at lower pressures, you can get away with using adhesives. ive used epoxy for my first pneumatic spud gun and it still works well

by the way, what kind of valve are you using? here in aus, ball valves are the most economical (and they still cost $8 for a cheap one) and they dont dump air very well. you could make a piston valve and use a ball valve to activate it

Yeh ill probably just get it to fire darts, but i wanna see if it actually works before i start trying to shoot shit out of it.

Not sure what sort of valve, but it opens when u press the button and closes when u release. I was thinking of either using an empty bernzomatic fuel cylinder or getting some 40x5mm aluminium tube with 2 end caps and going from there. Advantage of the aluminium is that i can make it however big i want, but it'll cost more in the long run. Bernzomatic tank would be good but i dunno how to refil it.

if you find that you cant make a good, quick release valve, you could use two (or even three) identical ball valve and connect each one to one chamber. rig up your trigger so a firing motion would open all three at the same time. it still isnt as good as a piston or sprinkler valve, but with three chambers rigged to one barrel, it should be alright. make a smaller chambers if youre doing this, or it will take a long time to fill up, and youll waste a lot of effort

Awhile back a totsean was building a bb gun thing so I took apart my bb pistol and modeled the trigger for him so he could see how it works.

http://img375.imageshack.us/img375/4497/bbgun003640x480cs2.jpg
http://img371.imageshack.us/img371/9449/triggerrenderpa3.jpg

Doesn't apply to your project, but if you give up and make it spring powered, this may help.

BB Machine Guns, niggah! Not hard to make, much more awesome fun than making an air rifle. May as well spray BB's everywhere at a high rate of speed if you're making something yourself (which can never have accuracy), yeah

http://www.burntlatke.com/bb.html

http://www.spudfiles.com/spud_wiki/index.php?title=BB_machine_gun

http://www.geocities.com/bbmachinegun/

maybe you can get some ideas here
http://www.offroadfabnet.com/forums/showthread.php?t=3954


http://img.photobucket.com/albums/v293/Hank-Chinaski/Tippmann%20A-5/DSC01828.jpg