Hello all, my first cannon ever! All aluminum piston valve

[Dirtman]

Tech thanks! this is the kind of criticism I'm looking for! The piston diameter is 3.5" and the barrel sealing surface is 2.25". So far in my test fires I've never herd any honking noises and I don't "think" the piston is moving back and forth during a fire. The noise is consistently one loud bang and a second of hissing while the chamber fully drains.

One thing I didn't like in other designs I saw online was putting an equalization hole in the piston. My piston is completely sealed (yes it still moves freely) and the pressure is equalized externally and then the chamber and pilot are completely shut off from each other before firing. I thought this would help make sure the piston would travel backwards faster and more efficiently. I'm not sure if this was a bad idea or hurts performance considering this is the only cannon I've ever fired.

I'll take a video and make sure to get a good sound clip on saturday.