Been there — built one after a night out and was shocked how far a potato went. Fun as hell, but they’re dangerous and can be illegal; please be careful, keep people and property well away, and use proper safety gear.

Hi everyone, I’ve been building a pneumatic cannon using 2" PVC, a 120 psi compressor, and a quick-connect valve, but I’m having an issue: the spud is only firing reliably about 1 in 3 shots. The pressure gauge reads full, the valve seems to open correctly, and everything is sealed, but the projecti...