Need some ideas for a Air powered golf ball cannon

[Technician1002]

and the second is it would slip into my barrel the piston is the same size as my ID of my 1"pcv, on another note,

I would recommend stop all work until you understand how a piston valve operates. The piston moves when the chamber pressure acting on the area on the front of the piston is a greater force than the air in the pilot holding it closed. With the piston OD smaller or small as the ID of the barrel, there is no area left for the chamber pressure to act on. It's not going to work with an OD the same as the ID of the barrel unless you provide a mechanical way to open it. My QDV is an example of the piston with the OD the same as the barrel ID. It is pulled open by hand.

[Northir]

yea i think ive got things figured, my piston chamber is the T so my piston needs to be the width of it, working on boring out my 2" T not going so well, i have to do it by hand, no press, i tried on a scrap T and i ended up chewing in to the side wall of the T

EDIT: i think my hole saw is to harsh for my piston, i kinda wish i had one i could take apart and look at then im sure id under stand how to build this stupid thing

EDIT: So im an idiot. . . and sorry for my lack of understanding, but i believe im starting to under stand, i dont cut out the lip of my piston T unless its in the way of my piston, ill get a picture of what i think i should be doing
@tech i under stand how it works just not how to build the stupid thing
if that grey piece of PVC was my piston the same size as the ID of my 2" PVC and the white piece of PVC was a peice of golf ball barrel id be on the right track?
SO i cut a bunch of wood @ 60mm caus thats the closest think i have and glue them together sand/grind them till they just barely fit in my 2" PVC and thats my piston then i have my barrel seat half way into my T that gives me the face for my piston to seal against . . . piston is 2" and barrel is 1.7 inch inside so my piston is smaller than my barrel

[Northir]

So i have what i think my valve should look like

and


so i want to glue it all together but didnt want it to be a screw up since i put so much time and work into it

EDIT: >.< sorry for double post