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pneumatic marker project

Posted: Thu Feb 28, 2008 2:15 am
by jackssmirkingrevenge
Following on from the critically acclaimed pen-gun project, it was apparent that 0.1 inches is far too low a calibre for reasonable power, even at high pressure. I was pondering the possibility of making a second version with a thicker chamber and a larger - probably 0.177" for BBs - barrel, that could be made to fit in the body of a whiteboard marker, or at least made to look like one. Nothing sinister about this deception, it's just a personal facination with covert weapons :) The design I have in mind would include a cap to fire the schrader pilot, as well as an integral supressor by adding vents in the muzzle end of the barrel that would exhaust into the hollow front portion of the body.

The diagram is pretty much self explanatory:

Posted: Thu Feb 28, 2008 2:20 am
by Davidvaini
A sharpie would be sweet but idk if its too small for your ideas.

Posted: Thu Feb 28, 2008 2:26 am
by jackssmirkingrevenge
The external diameter of the tube I intend to use as a chamber is around 0.6", I'm sure I'll find a marker it will fit into.

Posted: Thu Feb 28, 2008 2:28 am
by Novacastrian
Is this a reproduction of the little pistol, 3000psi, made in Pakistan- often linked to keyring thing?

Posted: Thu Feb 28, 2008 2:33 am
by jackssmirkingrevenge
Novacastrian wrote:Is this a reproduction of the little pistol, 3000psi, made in Pakistan- often linked to keyring thing?
Made in the UK by Steve Harper actually :wink: that uses the Brocock mini cartridge that looks something like this internally, the firing pin literally knocks the valve open.

My design on the other hand is a exhaust valve piston launcher that's basically an evolution of the pen-gun project.

Posted: Thu Feb 28, 2008 2:36 am
by Novacastrian
Furry muff, what pressure where you planning, would a micro pump be in the making or will you utilise existing facilities?

BTW: You would have to be sure to place your gun the "right" way up in your pocket! Otherwise you may have a slug up side your head. :D

Posted: Thu Feb 28, 2008 2:39 am
by jackssmirkingrevenge
I'm hoping to go high with the shock pump, the problem with the pen-gun is that beyond 250-300 psi it starts to leak from the barrel, so I never exploited the advantage of the tiny chamber to go higher. Of course the gauge is useless at this pressure but I intend to pump as hard as I can, we'll see.
Novacastrian wrote:You would have to be sure to place your gun the "right" way up in your pocket! Otherwise you may have a slug up side your head.
Or in my balls, it's a lose-lose situation :roll: but I don't plan on carrying it around so I'm ok ;)

Posted: Thu Feb 28, 2008 2:47 am
by Novacastrian
Looking at your diagram, it appears you have broken one of your nazi rules, namely D/4. :D

Posted: Thu Feb 28, 2008 2:52 am
by jackssmirkingrevenge
I never said it was to scale ;p

Posted: Thu Feb 28, 2008 2:56 am
by Novacastrian
jackssmirkingrevenge wrote:I never said it was to scale ;p
I don't want to hear about your bedroom antics! :D

Posted: Thu Feb 28, 2008 3:06 am
by jackssmirkingrevenge
Fine, yeesh! Gained a bit of chamber volume too :wink:

Posted: Thu Feb 28, 2008 3:09 am
by Novacastrian
Good boy, that's better :) Have a cookie. :lol:

Posted: Thu Feb 28, 2008 3:10 am
by jook13
why not make the chamber the whole length? that is what I am seeing right? the chamber being only about 1/3 the length of the whole gun.

Posted: Thu Feb 28, 2008 3:13 am
by Novacastrian
I think silencer capabilities may convince otherwise :wink:

Posted: Thu Feb 28, 2008 3:24 am
by jook13
yeah that makes sense to me. the whole covert secret james bond weapon thing... I just thought with a spudder this small you would want as big of a chamber as possible. none the less, I really cant wait to see it completed. even though I am new, I have learned that jsr's projects are worth looking forward to (I have been kinda a lurker)... :D