configuring a design to fit a piston valve

[JDP12]

Hey all, i really want to build a shotgun style golfball gun similar to Goats MCS, 1st picture below-break action. However, i like the modular look of the second gun pictured- boogieman's zooka.

I want to keep the looks of both, but i want to use a piston valve in it- either barrel sealing or coaxial. I'm looking for about the same performance as a combustion gun that fires golfballs. The big problem is getting that streamlined look. Now i know someone will tell me to make a coaxial.. but the thing with that is that a) if i want it to be break action, i'll have a lot of dead space, and b) i'll need the chamber to be fairly long in order to get the volume up with such a big barrel in it, and i want to keep it modular- preferably 3 feet max.. now i don't know what to do to keep the streamlined look, so any help is greatly appreciated.

My biggest thing is the streamlined look..

oh and in case you're wondering why i can't use a sprinkler valve, it's because a) i'll be using CO2 and b) i'll be operating at higher pressures, so then a coax might work.. honestly i have no idea right now any help would be great.


EDIT: i think i'll do a coax style thingy maybe

<img src="http://i167.photobucket.com/albums/u148 ... ure025.jpg">
<img src="http://advancedspuds.com/stuff_009.jpg">

[THUNDERLORD]

Yeah, we'd all love to have one just like those.
And so build one if you want it so bad.

[JDP12]

ummm i'm going to, did you read the post though??

[jrrdw]

Are you planing on a bore big enough to shoot golf balls? Or was that a example? With a smaller bore a stream lined launcher would be easier to configure, I think.

[JDP12]

yea, a golf ball gun. I think i'm going to go with a coaxial, but i think what i might do is put a slightly smaller piece of PVC into the chamber to act as the "barrel," then bring it up to golf ball barrel outside the chamber, that way i get a bit more chamber volume. not sure about restriction of air though? IF i put a 1" or 1.25" of PVC in the chamber instead of 1.5" i don't think it would restrict flow too much, do you? I'll run it in GGDT once i get home- can't run exe files here at school..

[jrrdw]

1" shouldn't choke it very much at all, not enough to notice by eye but a chrony would notice I think. As for the GGDT, look around the forum, I've seen 2 seprete threads started about it now, I don't know if I'd trust it or not.

[JDP12]

well it'll give me a start... but i dunno yet.

[clide]

Why not extend the piston to the sealing face rather than the sealing face to the piston.
http://www.spudfiles.com/forums/preload ... t8702.html

Known as a toolies style valve to the people who have been around here awhile. http://my.freeway.net/~toolies/

It will allow more chamber volume and would probably be more efficient.

[judgment_arms]

That’s what I did, Clide, saves a lot of space.

Funny, when ever I think I’ve come up with something new, I find out Jack beat me to it…



But yeah, your best bet would be what Clide said.

[JDP12]

wait... soo i get it... i think.

Thanks guys

yea i got it now