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Is this about right?

Posted: Fri Jul 31, 2009 10:18 pm
by Alucard
Well, i've finally decided on a Pneumatic Cannon, I know it wont be the most accurate of the bunch, I also know I could probably do better with a production air rifle. But i've decided on this. I want to use a system similar to the one on this rifle. http://www.spudfiles.com/forums/m25-sni ... 15093.html I believe that it is a QEV System? With a bolt-style(Piston?) Valve. I do not know what the trigger system is however, I would like to build one more similar to that of a real rifle, I would also like to replace the pop bottle with PVC or Copper or some other pipe, what would be better to use a Quick disconnect or Schrader? Chances are I will replace the wood bolt holder with one I will machine my self out of metal (Ill add a nice weaver to the top as well.) I don't care about semi auto anymore, but I would like any advice you can give, and also any tip's on making the gun shoot at least 5 shots without having to be refilled. I hope I made some sense out of this lol.

Re: Is this about right?

Posted: Fri Jul 31, 2009 10:23 pm
by spudtyrrant
just go one shot with a pvc gun if you want to make a multi-shot gun go with this http://www.spudfiles.com/forums/brass-t ... 17827.html its not the easiest project to make and you will need a high pressure pump http://www.spudfiles.com/forums/easy-st ... 13277.html. but for your first i would go with this one it seems solid.
p.s. there is a tutorial on how to build that exact gun here http://www.instructables.com/id/25MM-Pn ... per-Rifle/
P.S.P.S it is a modified sprinkler valve he is using http://www.youtube.com/watch?v=A3EOdNP6Iag

Posted: Fri Jul 31, 2009 10:49 pm
by Alucard
Not quite, I am thinking something more like this,Image(Of course I forgot to add the Thumb whole, and the bipod, also Sorry bout the terrible quality and hand writting I just drew that in under a minute lol.) and using a air compressor or scuba tank to fill it, possibly a really good pump to fill it. Im also looking at most of the tubing being metal. Multi shot would be nice, but it does not really matter.

Posted: Fri Jul 31, 2009 11:25 pm
by spudtyrrant
woops i didn't even follow you link sorry i just saw 25 in the link and immediately guessed it was that one.

Thats a homemade qev basically a barrel sealing piston valve. i think someone has linked to you on one of you previous topics.

To get multiple shots it would mean a drastic decrease in power unless, you made your barrel smaller.

Be sure to use thick stainless or other suitable metals, scuba tank puts out a lot of pressure, and any fitting you will find @ your local hardware store would likely not be sufficient, you will probably have to machine your fittings, if this is not possible i suggest using lower pressures or trying to get a hold of hydraulic fittings.

mind you a project like this will not be cheap be prepared to fork out at least a few hundred dollars for just a simple single shot that can handle 3000psi. since it is your first one i would keep it simple and sturdy and make a single shot but if you want multi shot.... i would use a valve such as this for a gun like yours http://www.beemans.net/images/Operation%201n-29k.gif it will not be simple to make but it will give multiple shots and handle the pressures you want to use

Posted: Fri Jul 31, 2009 11:28 pm
by Alucard
Okay, lets say I drop the psi down to 400-600 would that be good, what can I expect from that? I want to have fun, but I would rather not go over 150$ on this one, I can make the stock my self, and would rather not make anything else but the rifled barrel after I figure out that it works, should I choose a smaller round? Any chance you can give me a link to making a Piston valve and qev or am I going to have to do this all on my own? Edit: im cool with single shot.

Posted: Fri Jul 31, 2009 11:38 pm
by frozebyte
Firstly, it isnt a good idea to restart a new topic on the same thing. Just post this on your previous one.

Second, im very sure i already directed you on your previous topic on the HOW-TO SECTION to find out about piston valves and how to BUILD THEM. Its already on a sticky so theres not much reason why we should supply you with the link.

The price of the spudgun is going to be according to how expensive these fittings and pipes are at your location. The sketch you drew, it doesn't make any sense comparing the two (trigger location in accordance to scope in both pics) It doesn't tally right.

Check out MRR's tutorial on a piston valve and scale it to whatever size you're looking for,

You just have to replace his trigger mechanism(those parts behind the tee) with a blowgun or similar and fit on your chamber with the L on the Tee and voila, you have your spudgun ready to fire.

Thats exactly how you want it to be, but note that your trigger is not going to be below the scope with your setup.

PM me for help :)

EDIT: woah that sounded very monotonous and isn't pleasant to read :roll: :roll: