Semi-Auto CO2 Pistol

Building or modifying BB, Airsoft, and Pellet type of guns. Show off your custom designs, find tips and other discussion. Target practice only!
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POLAND_SPUD
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Sun Jun 20, 2010 12:35 am

I think he's asking about the loading mechanism and all the internals :wink:
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MrDinoRAWR
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Sun Jun 20, 2010 1:07 am

Well yes. The loading mechanism will be semi-Automatic.

I have started making a Sniper Rifle aswell :)
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Sun Jun 20, 2010 3:33 am

django wrote:the Design with the Ball Valve,the pistol would be too big! and waste too much co2 using a Ball Valve
Perhaps, using standard fittings, but with some judicious use of epoxy (or custom machining if binary adhesives are not your thing) it can be made as compact as a normal pistol. Another idea which will help is having the thing connected through a remote line to an external tank that can be carried on a belt or similar, assuming you have access to such paintball accessories in Oz.

The point of having a detent is that the ball valve only has to open a tiny amount to pressurise the chamber until the pop-off pressure of the detent is reached, and it should be spring loaded to re-close quickly.

I might just have to build something similar to prove the point :P
hectmarr wrote:You have to make many weapons, because this field is long and short life
MrDinoRAWR
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Sun Jun 20, 2010 4:38 am

Hi jackssmirkingrevenge.

Thanks for your input. I have been looking around and sketching valves and mechanisms used in manufactured airsoft pistols. I have come down too some sort of set-up using a hammer/knock valve and having either a blow back or plunger to slide the chamber open to reload. I don't know the technical names for them. Will hopefuly be uploading a scaled picture of my internal mechanism.

Thanks.
Tyronnne

P.S. Here's a link to heaps of animated valves. http://paintballlibrary.com/main2/page_10732.html
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django
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Sun Jun 20, 2010 6:59 am

I have an idea, how about using a system like the DROZD BB gun uses, if I can find a similar Solonoid that will knock on a small hammer valve of some sort when the triggers pulled?......


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jackssmirkingrevenge
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Sun Jun 20, 2010 7:36 am

django wrote:if I can find a similar Solonoid that will knock on a small hammer valve of some sort when the triggers pulled?...
It can be made to work, of course, and I believe you can also purchase innocent looking Drozd circuit board to save you the control headache - however incorporating batteries and a solenoid isn't exactly conducive to compactness, is it?
I have been looking around and sketching valves and mechanisms used in manufactured airsoft pistols. I have come down too some sort of set-up using a hammer/knock valve and having either a blow back or plunger to slide the chamber open to reload.
What sort of power do you expect from this design? If you want to do some serious damage, it will have to run off several hundred psi, for which airsoft designs might be unsuitable.
hectmarr wrote:You have to make many weapons, because this field is long and short life
MrDinoRAWR
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Sun Jun 20, 2010 7:43 pm

Hi.

Im really wanting about 180 -250 fps. That would make me happy.... Im going to make a single shot, with the mag, just pull the slide back ontop to re-cock and load. I'll make that first and then blend in something to make the slide go back itself, maybe using a bit of gas being blown into a plunger?..

Thanks
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Mon Jun 21, 2010 5:26 am

MrDinoRAWR wrote:Hi.

Im really wanting about 180 -250 fps. That would make me happy.... Im going to make a single shot, with the mag, just pull the slide back ontop to re-cock and load. I'll make that first and then blend in something to make the slide go back itself, maybe using a bit of gas being blown into a plunger?..

Thanks
I thought you were after a high powered Air Pistol??, maybe you have an airsoft pistol im mind?. I personally am looking to build as high powered as possible .177 steel BB pistol but wonder if I'll ever figure out how?.

A pistol shooting only 180-250 fps is just too weak for my liking but depends on your shooting intentions?,Airsoft skirmishing then thats good enough FPS I guess?.....
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Mon Jun 21, 2010 6:02 am

As django says those are pretty low power expectations, you can do better with a simple blowgun as a valve. By having a detent - some sort of seal that retains the projectile until enough pressure builds up behind it to pop it out like champagne cork - the efficiency of the valve is irrelevant and you can attain higher power than is normally associated with certain types of valve.

Take a look at this project, very good performance using a standard blowgun as both valve and pressure chamber, albeit for single shot. For a multi-shot though you will need a bigger chamber and/or higher pressure, meaning strong enough construction to take the strain and a suitable filling source.
I personally am looking to build as high powered as possible .177 steel BB pistol but wonder if I'll ever figure out how?
I own two commercial multi-shot CO<sub>2</sub> pistols so the drive to roll my own in this department isn't so great, however I feel you pain, once I sort out the sentry gun (new take curing as we speak, watch this space ;)) I'll try and develop something you might be able to make. I tried and failed with this volkspistole attempt but I'm sure I can do better ;)
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Mon Jun 21, 2010 6:51 am

Well I was awake thinking about this last night and the only way out I can see is to use a similar Solenoid( but much smaller) to what the Drozd uses and make some sort of hammer valve that the solenoid strikes.

I wonder if I could smuggle in a co2 pistol hammer valve and use that? I suspect trying to find a small but powerfull solenoid valve that doesnt need a lot of power to operate will be hard to find. I know this means battery's etc but at least I'll have a working pistol even if its a little bigger than I intended
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POLAND_SPUD
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Mon Jun 21, 2010 6:56 am

if you have a regulator then you might as well use a 3 way solenoid valve as the main valve (or an indirect acting manual valve)
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Mon Jun 21, 2010 7:05 am

what you need is a stem valve - basically a blowgun style valve with the trigger removed. A typical metal blowgun is good for 450 psi but if you want to use unregged CO<sub>2</sub>, you'll need to get a pressure washer valve, not too expensive off ebay.

Image

You would have to set up the solenoid (or to save complication, wiring and batteries, mechanical...) hammer to strike the part where the handle pushes down on the stem on the valve.
Last edited by jackssmirkingrevenge on Mon Jun 21, 2010 7:09 am, edited 1 time in total.
hectmarr wrote:You have to make many weapons, because this field is long and short life
MrDinoRAWR
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Mon Jun 21, 2010 7:07 am

.....To be honest, im scared of getting my hand blown off. We used too blow doors of their hinges with 12g Co2 cannisters. <---- (Don't think im alowed to say how). Im wanting a high powered pistol too, either using bb's or air-rifle pellets. I went scavenging at my uncles today, found some tubing and a awesome spring :lol: ...Tubing is to small for a bb, about the right size for a pellet though. Im going out too the steel place tommorow to get a meter of 50x25x1 ... That alone has changed my design by 5mm width, but will be okay.
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Mon Jun 21, 2010 7:36 am

MrDinoRAWR wrote: We used too blow doors of their hinges with 12g Co2 cannisters. <---- (Don't think im alowed to say how).
i think i got a good idea on how you did that xD
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Mon Jun 21, 2010 9:58 pm

Yes MrDino, I was more wondering about the actual mechanism that will reload the ammo. I knew you were going for semi-auto loading, I was asking how :wink:
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