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Small Airsoft Coaxial Pistol

Posted: Tue Jan 13, 2009 7:35 pm
by CrashTestDummy II
I just finished this recently, and it's a bunch of fun to plink around with in my yard. This is also my first (working) coaxial. :D

The chamber is made from 3/4" pvc, and the barrel is a 12" long piece of stainless steel pipe. I'm not sure of the exact diameter of the barrel. I just went into Ace with a couple of airsoft BBs and looked for the best fitting pipe :roll: . But the fit is pretty good. Just enough for the BB to take a second or so to roll down the tube when the piston is sealing the breech end of the barrel.

The piston is made from hot-glue, which was cast into a section of 3/4" pvc for the mold. The sealing face is a piece of neoprene, glued to the front of the piston.

The highest pressure that I've taken it up to is about 145-150psi. The coupler on the front of the gun looked a little suspicious to me. I got it at Ace hardware, in a bin that said that the couplers were pressure rated, but the plug doesn't fully fit into it, and it looked a little short in general, so I think it might be DWV. :? Anyways, here are some pictures...


<a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... erview.jpg" height="200" alt="Overview next to a ruler"></a> <a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... Valves.jpg" height="200" alt="Pilot side"></a> <a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... Muzzle.jpg" height="200" alt="Muzzle"></a>

<a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... ryHole.jpg" height="140" alt="Entry Hole"></a> <a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... itHole.jpg" height="140" alt="Exit Hole"></a>

Posted: Tue Jan 13, 2009 7:49 pm
by jor2daje
That looks pretty cool what are you using to keep the barrel centered inside the chamber?

Posted: Tue Jan 13, 2009 7:51 pm
by sputnick
Wow that looks like fun, the small guns have always been my favorite!

I have actually been thinking about building something like this, but only if I could find a suitable barrel for pellets, then I would make a whole rifle out of it. Speaking of which, if you extended the line from the T to the blowgun, this would be perfect for a small stock, a sniper air soft gun!

Well, you have inspired me enough to go design one, maybe me and my friend will build one ( we have always talked about making a high powered pellet gun) if we find any time after exams... 10 days!

Posted: Tue Jan 13, 2009 8:55 pm
by Cosmic Muffin
nice clean construction, put it on a wood stock. would make it look like gods own creation :P
its deffinately one of the best smaller guns i have seen on this forum

Posted: Tue Jan 13, 2009 9:54 pm
by CrashTestDummy II
Thanks for the feedback :)

To keep the barrel centered, I cut off the top of a 3/4" plug and dremeled it down to fit inside the 3/4" pipe. I just cut out sections so it wouldn't restrict flow, and then drilled a hole in the center for the barrel to pass through. The support is epoxied onto the barrel. Sorry if the description is confusing. The support looks like this:

<img src="http://i119.photobucket.com/albums/o139 ... upport.jpg" alt="barrel support">

Thanks again!

Posted: Wed Jan 14, 2009 1:44 am
by jackssmirkingrevenge
Very nice :) for small calibre single shot launchers I would normally recommend a smaller chamber and high pressure from a shock/fridge pump, but as a fun little plinker this fits the bill perfectly.

Posted: Sun Jan 18, 2009 11:54 am
by mark.f
Very nice. Welcome back CTD, it's good to see you around again. I always liked your work.

Posted: Sun Jan 18, 2009 11:17 pm
by blind909
Nice. I like it, small, portable, and POWERFULL.

Posted: Mon Jan 19, 2009 12:38 am
by inonickname
I like it. Have you checked if it's legal for your field (fps)?

Posted: Mon Feb 02, 2009 2:12 pm
by trae08
This is a nice gun, Im a fan of plinkers myself. Great work.

Posted: Mon Feb 02, 2009 3:22 pm
by jonnyboy
Do you have to kick up old topics?
inonickname wrote:I like it. Have you checked if it's legal for your field (fps)?
This isn't exactly something I would would call ideal in airsoft especially against aeg's...

Posted: Tue Mar 24, 2009 3:01 pm
by poppamies
cool gun! wen i saw that damage piucture i think "i dont want to get shot by that!"