Need Help GGDT'ing my gun.... Please help...

[spudkpi]

I have just made a coaxial piston cannon and i would liek to GGDT it but i dont know the exact inner and outer dia. of the chamber or the flow coef. or the friction of the projectile or any of it... if someone could give me a link to a walkthrough or just help me out I would greatly appreciate it... thanks.


Here's my gun: http://www.spudfiles.com/forums/viewtopic.php?t=3079&

[Steve-]

i need help too, i can't figure out why the outer diameter would change anything because isn't that only the pipe wall width which only changes the strength of the pipe???

edit: i think i got it, the outer diameter is the inner diameter of your chamber and the inner diameter is the width of your valve input

new edit: i looked on the website and acctually the inner diameter is only for coaxial meanin the outer width of the tube inside the chamber.

newer edit: benstern beat me too the punch

[spudkpi]

is it really? thanks man ill try it

[benstern]

Inter diameter is only used if you have a coaxel cannon. Just put the inter diameter (exact not nominal size) of you chamber in the Outer Diam box.

[spudkpi]

Thanks benstern.

[Shrimphead]

If you were to go to the "other" section of this site, then to "pipe info", you could find out the pipe dimensions.

[spudkpi]

Yep there it is.... with a paintball it shows 635 ft/s at 80 psi.... thanks guys