First ever pneumatic potato cannon

[ToneTheDog]

So I’ve wanted to get into building spud guns in the past and since I just got my first job I figured why not try and build one. Its one of those coaxial (?) ones with a piston in the back. Sadly its not really working. I dont think the chamber or barrel are the problem. And the valve in the back seems fine so I think its the piston but im not really sure to be honest. Just looking for any advice or help. (I will send pictures later im not hone right not)

[jimmy101]

Welcome to the forum!

Post some pics and specs, people are usually glad to help (or at least chime in with criticisms )

[ToneTheDog]

Ok so im home now. The barrel is 2” and the chamber is 3”. The piston was just a mason jar filled with a 3” washer glued to it. My cousin helped me earlier. So when I had the piston in and he pumped aire into the cannon, the projectile we had used moved along the barrel which leads me to think its something to do with the piston. (im not too sure how to post images but i think i got it)

thanks for the warm welcome!

[jackssmirkingrevenge]

Welcome!

The piston was just a mason jar

oh.

...which leads me to think its something to do with the piston.

uh huh.

I don't think we need pictures, it's probably time to rethink your piston