SpudFiles

This is built as a standard barrel sealing valve and may be able to "mod" onto existing barrel sealing cannons. A spring holds the piston against the barrel, air is vented from the chamber directly into the pilot area and pushes the piston back, once the piston opens past the chamber, the piston snaps back and all the air is vented into the barrel, then the spring pushes the piston back to its starting position. I did not draw the auto-bolt though, you could use Clide's idea. By adjusting the spring's power you could adjust the rate of fire and how much pressure goes into each shot.

This is a simpler version of my other idea, it also only has 1 moving part which makes it more reliable. All you would need to do to "mod" a regular barrel sealing piston valve would be to plug the normal dump valve, add the chamber-pilot valve, and throw in a spring. Should be easy.

Man i've been a mechanic for 25 years, the 1st auto pneumatic is the one to develope. I'm collecting parts rite now for my pneumatic, i'm thinking scraping the stanard piston valve i was gonna use and build the auto desigh you posted, it will take more time to collect the parts, but i think it will be worth the wait and effort. My projected time for complection is mid summer, some time in July. I'll post pics during the build, and finished cannon. Thanks for the good idea!

Cool, somebody is going to use my idea. I'm going to try and build this too, I've just got to get the supp lies. I think I am the first person to ever design an automatic, pneumatic gun without any electrical components. I'm gonna try and build this soon. Yeah!

i made a small experiment to test this and the piston got all smashed up but im shure it will hold with a stronger piston.

Thank you for the information, I'll make sure I use a strong piston and make sure everything is smooth. Did it work otherwise though?

A thought:
As you are using a face sealing arangement on the barrel, wouldn't pressure in the actuation zone drop and prevent the exposure of the chamber? (unless your 'pilot' valve was larger than your bore diameter, but that's silly...)

Furthermore, for saftey purposes, I reccomend sticking a pin in a dremmel and making a <i>very</i> small hole in the actuation zone (area anterior [in front] of the piston).

Notice that the piston face is sunk into the piston, this allows it to open some amount until the chamber is opened, then the piston will snap back and ALL the air will go in the barrel. You would just need to add an O-Ring onto the barrel inside the chamber.

P.S. Did you mean put a hole in the chamber wall, if so, that would slowly drain the actuation zone when I'm done firing, that is if there's any air left in it.

Atlantis. I think he dose mean to have a tiny hole in the chamber, but that hole could save you the actuating area blowing up if the piston gets jammed. Could save you an eye/life

I see, I could just put a pop-off valve.