SpudFiles

Well it took me quite some time to build this but I am so glad I finally finished it.
This is an all metal gun with a berrel sealing piston valve. The valve, along with the rest of the gun, is 3/4" steel. The piston, though, is made out of a highliter cut in half, filled with epoxy, and wrapped in ducktape. It fills through a male quick connect atatched to a ball valve and thats also where i pilot the valve for now. Berrel is 9/32" brakeline and my primary ammo is 1/4" steel slingshot bb's.
This gun is very powerful and fun to shoot. I hope ya'll enjoy it.
Here are some pics of it.

that looks great. Though it looks like your pilot volume is rather large, unless your piston is longer than the tee. but yeah, good job man.

Looks good! What did you use for a sealing lip? Post damage pics!

I am though jealous that everyone can build a piston valve but me...

Thanks for the comments guys. Hopefully i could get a video of it sometime this week but i'm not sure.
The pilot volume isn't too big because the piston is almost 2" long and is housed in the pipe nipple behind the tee.

@Noob of Noobs, for the sealing face i just found this piece of thick rubber and put it on my piston. also don't give up on making a piston valve, it took me for ever to get this thing working.

In the future I hope to make a stock for it and make it breech loaded. Any suggestions?

Dont worry noob of noobs im still making piston valves and my first one i made didnt work for me. I plan on building another piston vavle gun but im not sure what size i should make the gun or what kind it should be (copper or pvc) so i know how you feel. But eventuall we will get it

Nice gun. Is this all soldered or compression fittings?

EDIT: Umm breech load maybe hard considering the size of your barrel is considerably small. But its still possible you can use a breech system where you unscrew the barrel, load the ammo, then rescrew the barrel back, or you can have a vertical feed, or you can get a barrel thats a little bigger than the one you have, then you cut a rectangle into the bigger barrel, and sleeve it onto the smaller barrel and attach that to the tee. Use a hose clamp and a screw to to lock the barrel in place once you make a groove into the bigger barrel so that the screw can fit in there. It would be much easier if you look at the how to or other cannons that have breech loading systems.

Look at this and it should help you. Just use these same instructions except using a smaller barrel.

LikimysCrotchus5 it is not soldered it is just threaded steel thats all.
And thanks for the suggestions on breech loading.