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Home made co2 Airpistol?= need help / ideas

Posted: Sat Jan 23, 2010 5:44 am
by django
Well guys, For years ive wanted to make a co2 Powered Airpistol, preferably Semi Auto= over the years ive googled and tried to come up with a way to do it but still not been able to do so! :roll: .

I have a few mates that have wanted an Air Pistol for a long,long time and I get asked a lot if Ive been able to make one yet!? here in Australia I cant get Co2 Airpistol internals to use for construction so have to come up with some other way?.

I was thinking of somehow modifying a co2 bike inflator to a hammer valve but I dont think it can be done and also they only output at 100 psi or so from memory?. I wanted to have the pistol shooting the co2 at full 800 psi pressure as per .177 co2 pistols do, I dunno maybe its not possible? any help MUCH appreciated


also looking for air pistol schematics to help try figure out how I can make such a pistol? , ive not found much so far

http://www.pyramydair.com/schematics/rwsmodelc225.asp

Posted: Sat Jan 23, 2010 6:01 am
by Lex
Maybe something like this or that?

But be warned, unregged CO2 is nothing to play around with if you don`t know exactly what you are doing!

Posted: Sat Jan 23, 2010 6:12 am
by inonickname
What kind of materials and facilities do you have available? If you have a decent shop setup I'll dig up a few links for you.

Re: Home made co2 Airpistol?= need help / ideas

Posted: Sat Jan 23, 2010 6:27 am
by jackssmirkingrevenge
django wrote:I was thinking of somehow modifying a co2 bike inflator to a hammer valve but I dont think it can be done and also they only output at 100 psi or so from memory?
As far as I know they give the full pressure, I took apart my ultraflate and it looks like a simple sprung ball pushed down by a pin, no sign of any regulation.

I think the easiest possible solution that gives good performance would be to combine an inflator with a tee breech. The lowish flow rate of the inflator would be negated by the seal/detent that would hold the BB in until a certain pressure was reached at that point if would be the equivalent of a burst disk valve. Not sure if you have airsoft magazines avalable but I reckon Davidvaini had the right idea :) not to mention you technically have the option of full auto as long as the trigger is pulled.

You could also conceivably replace the trigger with a hammer if you want a "proper" semi-auto, are cap guns legal down under?

Posted: Sat Jan 23, 2010 7:54 am
by POLAND_SPUD
@jsr
yeah I guess he was right...
though I think it would be more practical if you build one with a small QEV or 3 way valve as the main valve (IIRC you have one, right ?)

you could even use the pneumatic fullauto / timer circuit as the main valve...

Posted: Sat Jan 23, 2010 8:01 am
by jackssmirkingrevenge
POLAND_SPUD wrote:though I think it would be more practical if you build one with a small QEV or 3 way valve as the main valve (IIRC you have one, right ?)

you could even use the pneumatic fullauto / timer circuit as the main valve...
Hard to fit in a pistol sized package though eh?

Posted: Sat Jan 23, 2010 8:22 am
by django
Yeh we Are allowed cap guns but NO Airsoft gear at all, the joys of Aussie Gun Laws :roll: as far as I was Aware those inflaters were regulated down!?. Maybe specific ones are?, I looked on the packaging of one here and im sure it said it only output at 100 psi? so I never ventured that way with one for a Pistol.

I had thought of a 1/8 Qev and Poppet valve like my Pitbull 9 Rifle( that uses 1/4 gear though) BUT I wanted the pistol to take full co2 psi as being a pistol the barrel will be small so power will be very low unless full co2 pressure is utilised.....

Posted: Sat Jan 23, 2010 8:26 am
by POLAND_SPUD
well not really... the valve that I used in that experiment was the only one I could get at that time... so it wasn't very compact

5mm valves are smaller than a box of matches... 1/8" valves are almost exactly the size of a box of matches.. 1/4" ones are slightly smaller than a box of cigarettes

so it wouldn't be that difficult to put a 1/8" valve into the pistol grip

Posted: Sat Jan 23, 2010 8:36 am
by urgle the danish cow
jacksmirkingrevenges idea works very well. a friend and i did the same thing some time ago and it worked well except for it shoots full auto and you have to reload constanly. it also works well if you bend a small section of tubing up and around ( so then on top of the bike valve) into a bb chamber and just a bbmg from there. resulting in a very small pdw airsoft smg. then agian thats not semi-auto. just throwing it out there

Posted: Sat Jan 23, 2010 9:19 am
by jackssmirkingrevenge
Time to put my money where my mouth is, I'm should give the inflator + tee breech a go :)

Posted: Sat Jan 23, 2010 10:18 am
by qwerty
How many shots do you think you could get with one cartdridge? I might give it a go if it's not to money consuming.

Posted: Sat Jan 23, 2010 10:51 am
by django
Yeh I tend to think it will spit out more than one BB at a time Jack!, but if tolerances are tight then maybe its possible?,Id love to be able to finally crack the making of a High Powered co2 Air Pistol. Not only would I be be happy but my friends would finally have an Co2 Air pistol!, if construction was easy enough that is?

Posted: Sat Jan 23, 2010 10:54 am
by jackssmirkingrevenge
I'm giving it a whirl as we speak, will post when I have something worthwhile.

Posted: Sat Jan 23, 2010 12:08 pm
by qwerty
Try making an inline hammer valve (abit like an XRV) i'll post a pic of mine an a bit.

Posted: Sun Jan 24, 2010 12:15 pm
by jackssmirkingrevenge
Here's a preview of the prototype for this idea curing, it's all pretty ghetto but as just a proof of concept prototype, it "only" has to work :P :wink:

I'm also making an extended chamber with a schrader fill valve and half a used CO<sub>2</sub> bulb so there's extra air capacity and I don't have to spend money on cartridges in the off chance that it works ;)