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Help on how repeating barrel-sealing valved airguns work?

Posted: Tue Nov 30, 2010 8:15 am
by jmez1996
Hi everyone.
I have basic knowledge and understand how barrel-sealing piston valves work and how they can be implemented into airguns.
What i dont understand is how people manage to make semi-automatic or even repeating airguns with these types of valves that dont completely empty the tank on the first shot.
here is a example of this being done:

any information about how this gun or other guns manage to do this would be much appreciated so i can make my own.
cheers

Posted: Tue Nov 30, 2010 9:08 am
by jackssmirkingrevenge
Here's one I had made:

[youtube][/youtube]

This is what it looks like internally:

Image

The vertical schrader is the air input, the horizontal one is the pilot. Note that the piston is a good fit but not airtight, so air can flow from the main chamber to the pilot chamber.

When the pilot is opened, more air can flow out of the pilot than can flow past the piston, so the pilot pressure lowers and the piston opens.

One the pilot is closed again, pilot pressure starts to rise again, the piston reseals and the cycle can be repeated.

Substitute the manual pilot for a pop-off valve which automatically opens once a certain pressure is reached, and you have full auto ;)

Posted: Tue Nov 30, 2010 9:25 am
by jmez1996
nice valve man but i dont quite understand it. still im looking for a explanation of the link above.

Posted: Tue Nov 30, 2010 9:38 am
by jackssmirkingrevenge
jmez1996 wrote:nice valve man but i dont quite understand it. still im looking for a explanation of the link above.
I believe it's this one, the maker is certainly a member of this forum so you can ask him directly ;)

Posted: Tue Nov 30, 2010 2:15 pm
by jakethebeast
yeah that jsr coaxial pistongun is good version of semi auto barrel sealer.


BTW i see those same printer cardridge tubes again :D :D

Posted: Tue Nov 30, 2010 2:34 pm
by wyz2285
lol that's my gun :D but the one in the video is this http://www.spudfiles.com/forums/build-f ... 21582.html :)

Posted: Tue Nov 30, 2010 5:53 pm
by clemsonguy1125
Heres mine, basic barrel sealer piloted by a hose gun chamber filled and has a spring behind the piston. Ask anything about it if you dont understand
http://www.spudfiles.com/forums/semi-au ... 21627.html