PVC Pipe is your friend
(I would recommend 100mm for the combustion chamber and a reducer to 40mm for the Barrell), you require an 'o' ring sealed screw end for the bottom of the combustion chamber (this aids in a rapid reload). PVC Glue to put it all together.
A pesio (sp) igniter embedded into a wooden pistol grip running your wires through a wooden dowl plug into the combustion chamber(assists in maintaining a superb overpressure)
A can of black spray paint, a wooden dowl plunger for loading ones' musket, a sack of spuds, some lighter fluid in a spray can (insert through the small hole in the combustion chamber).
Ram your spud in, fluid spray, aim, Fire! Chips for everyone. :ouch
So much fun, even made one in Bosnia.
