Anyway, everything was built from stuff I found in my scrap box (except the stun gun).
Some specs:
Chamber volume: about 60mL
Barrel: (I didn't bother with dimensions) The metal part that makes up the neck of some BBQ lighter
Ignition: Stun gun with screws
Fuel: Butane
Hope you all like it

Any questions feel free to ask Update:
I ran out of butane so I've gone on to propane (I didn't use it in the first place since fueling with butane was easier and more gas efficient rather than leaky like my ghetto propane setup)
I've also taped the taser to the body of the gun to make a sort of pistol grip (only taped on since I want to use the stun gun for other things as well)