SpudFiles

I have an idea for a very cheap piston involoving only 1 piece.
Put the ammo between the chamber and a ball valve, so when the valve opens the ammo acts as its own piston.

Methinks this is going to make a sticky mess in your ballvalve.

its something like the burst disk effect, infact, its going to work, very well if u use a good airtight ammo

That is most likely true but i was thinking aboiut using solid ammo like golfballs. That doesnt squish.