9mm Coaxial airgun

[Juggernaut12121]

I've wanted to build a smaller bore airgun for a while, I also wanted it to be more compact although that didn't work to well for me . I still like it though
The barrel is a length of aluminum round tube that's 3/8'' in ID (not exactly 9mm but close enough with wadding) and almost 1/2'' in OD by 3' long
Chamber is a 2' section of 1 1/4'' pvc pipe
The piston is a 3/4'' pvc cap filled with hot glue and topped off with a piece of sheet rubber (sorry I don't have a picture)\
I wanted to keep it somewhat small and simple so the pilot valve is a 1/4'' ball valve, and I need to attach a thingy onto the quick adapter on the other end of the ball valve
The backstop is a layer of weather sealing tape
I haven't gotten to really shoot it yet since the ammo is still in the mail, but it seems to work pretty well.
The stock is alright but in retrospect I probably should have used 3/4'' pipe and fittings instead of 1/2'', which I had lying around.

[fractal]

Looks well constructed

[Juggernaut12121]

Thank you

[jackssmirkingrevenge]

Nice effort! For a small bore personally I would have gone for higher pressure and a smaller chamber volume, you would be amazed at the difference in performance.

[Juggernaut12121]

Thanks! I would've made something more high pressure (out of copper or something similar) but I didn't have any way to pressurize it past 100 PSI (I have a floor pump and a small air compressor). Unless I'm missing some sort of technique or something (highly possible for me to be missing important or obvious knowledge)

[fenrir]

You can make a stirrup pump, or salvage a fridge compressor in order to reach higher pressures.

[Juggernaut12121]

Thanks! I've never heard of a stirrup pump before a few minutes ago, that'll probably be my next project


Edit: after looking a while I've figured out that I just called them something different, but I've never thought of building one

[jackssmirkingrevenge]

You can buy a floor pump that goes to 260 psi for not much $$$: http://www.amazon.com/Serfas-FMP-500-Bi ... floor+pump

That will more than double your available power...

[Juggernaut12121]

I thought about getting a shock pump for getting higher pressures in future guns, I found one for decently cheap (boasts 400 PSI)
http://www.amazon.com/XLC-High-Pressure ... shock+pump
Although I don't have any experience with them, I don't think they should be too hard to use

Btw JSR your picture and your quote are awesome

[fenrir]

Just don't use very large volumes. If you live in the US, I can send you mine for 25 dollars shipped, just PM me.