I intend to use an extruded steel tube with a hinged cover on the bottom with a hole in the middle. you take a shell which would be a smaller piece of pipe to fit down the barrel and put a banger in it with the fuse poking out the bottom. you then pack the top of the shells either with bbs or a solid shot then drop it down the tube. If all goes well the fuse will be poking out the hole at the bottom of the pipe and you can light it and when the bang goes off you open the hatch at the bottom and take out the shell.
before I go and build this and blow myself up anyone got any Ideas for improvement?
Without wanting to p*ss on your bonfire, I'd suggest not bothering.
Unless you're a site owner, that is, with a very hefty insurance policy, as I doubt any other organiser in the country would let you use a home made firework powered device.
may have to revert to my original plan of saving up for some of these.
