what is the best size barrel to buy 1.5 2.5 etc

thanks guys i think i found what i wanted. I'll stick to the original PVC Combustion. Thanks for the help guys

just send a link of what to do all i want is to have a portable spudgun of PVC pipes and shoot some tators

like PVC Pipes and stuff like that

do the screws go only partly through or touching the other side of the pill bottle?
How much hair spray do you need like 1-3 mL?

how can i make a descent Potato gun with just materials around the house. I want one that doesnt need pneumatics. One that can shoot like 50 yards or so

how far does it go