)I've recently made my first "spud gun"... well actually it's a small piece of PVC (2cm diameter x 6cm length). Both ends superglued with rubber O-rings (the ones you use for watertaps). On one end I've slightly plugged in a main wire (with 2 or more colored wires inside) to get a spark from a piezo ignitor. On the other end, I've enlarged the hole of the o-ring to fit in a 6mm BB.
For combustion I use standard hairspray and for oxygen i use a dual action bicyclepump (6 pumps)... it works awesome! There's no misfire and the combustion is much more agressive.
After this succesfull test, my next step is to seperate the piezo igniter and use some kind of connection (metal to metal) to pass the spark/energy from a handguard with a piezo trigger to the bolt loading the PVC round.
Later on I'll figure out a way if the recoil is enough to eject the empty case.
I'll post some pics soon!
