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Coaxial Pistol

Unread postPosted: Wed Oct 03, 2007 2:07 pm
Author: singularity
this was built about a year and a half ago, i didn't post for some reason i can no longer remember. it is the smallest coaxial i have ever built (though it doesn't break any records for its size) and i believe it was based of a design i found here a long time ago. its primary ammo is Nerf darts, and its a hell of alot more powerful than any stock Nerf gun i have ever used. the grip came from a dead airsoft FAMAS my friend had, in the bottom there is a small compartment which can be used to store ammo (Nerf darts)

...specs...

primary valve-----------1.25" diaphragm valve
diaphragm material-----1/8" neoprene rubber
pilot valve---------------115psi pop-off
fill valve-----------------schrader
trigger-------------------metal rod (actuates the pop off)
primary ammo----------Nerf darts
range--------------------50 to 80ft
operating pressure-----100psi
chamber diameter------1.25 inches
barrel diameter---------1/2 inch


...pics...

<img src="http://i78.photobucket.com/albums/j85/irwinner_2006/DSCN2162.jpg">

<img src="http://i78.photobucket.com/albums/j85/irwinner_2006/DSCN2163.jpg">

<img src="http://i78.photobucket.com/albums/j85/irwinner_2006/DSCN2164.jpg">

<img src="http://i78.photobucket.com/albums/j85/irwinner_2006/DSCN2165.jpg">

Unread postPosted: Wed Oct 03, 2007 2:08 pm
Author: spanerman
Man thats kool, and damage pics? great idea for a trigger 8.9/10 hehe

Unread postPosted: Wed Oct 03, 2007 2:57 pm
Author: MrCrowley
I've seen this before somewhere, maybe you posted it somewhere. Like before I love the trigger setup.

Unread postPosted: Wed Oct 03, 2007 3:07 pm
Author: ALIHISGREAT
i like the pistol look, and the Famas handle is a cool. also what size is the barrel, if its 3/4" you should test it with some paintballs

Unread postPosted: Wed Oct 03, 2007 3:29 pm
Author: singularity
there i edited the specs so the barrel and chamber size show up

Unread postPosted: Wed Oct 03, 2007 3:52 pm
Author: jackssmirkingrevenge
nicely done, you could have got more power by extending the barrel and disguising it as a suppressor and upping the pressure a little, small chambers love shock pumps ;)

Unread postPosted: Wed Oct 03, 2007 4:14 pm
Author: singularity
quote]small chambers love shock pumps[/quote]

i know i attempted to pump it to 160 using my bike pump once, but it went off at 120. i sat there wondering what the hell just happened then remembered i was using a 115psi pop off... im trying to find like a 200psi pop off thats not to big but as of right now i got noting

Unread postPosted: Wed Oct 03, 2007 4:15 pm
Author: goose_man
A true beauty. I really like your trigger setup as well. Supercool gun! Nice and compact...

-goose_man

Unread postPosted: Wed Oct 03, 2007 4:17 pm
Author: jackssmirkingrevenge
You could have the trigger rod push a lever that presses on the schrader stem :) assuming you kept your piston travel to d/4.

Unread postPosted: Wed Oct 03, 2007 5:22 pm
Author: singularity
You could have the trigger rod push a lever that presses on the schrader stem Smile assuming you kept your piston travel to d/4.


its a diaphragm and there is way to much pilot volume, i did try using the schrader to pilot it after seeing your pen gun but sadly it was very weak.

Unread postPosted: Thu Oct 04, 2007 12:05 am
Author: benstern
MrCrowley wrote:I've seen this before somewhere, maybe you posted it somewhere. Like before I love the trigger setup.


Thats what I thought too! I can swear I have see this before too.

Unread postPosted: Thu Oct 04, 2007 9:31 am
Author: flamerz14
:D nice one....now turn it into a carbine :twisted: :twisted:

Unread postPosted: Thu Oct 04, 2007 3:01 pm
Author: meatballs
singularity please dont try that gun above 100 psi. From participating in its construction, i know that the 1 1/4" male adapter and coupler were put together using a 1" coupler instead of a piece of 1 1/4" pipe. The 1" coupler was not a snug fit, with a millimeter or two of wiggle room around it. this means you don't have good contact for a solvent weld. also, it is not long enough to completely fill either 1 1/4" socket. Also, to avoid stains (which would have ended up painted over) primer was not used in assembly. so really, 100psi isn't in what i would consider a reasonably safe pressure range, except that i have used it at that pressure many times so i trust it not to fail. Also, the barrel cuts into the diaphragm a little at 100 psi, and it could get blown out since it isn't pressure rated. that wouldn't be a major problem as long as the barrel wasn't pointed at anyone, but still, not good. so i dont think it would be a good idea to exceed the limits of the 115psi pop off.

Unread postPosted: Thu Oct 04, 2007 7:23 pm
Author: VH_man
consider yourself an inspiration. time to make one of these, exept out of galvanized steel and .68ID aluminum tubing........... 200 PSI PB pistol? lol.