For the gun stock I glued two pieces of thick plasticard together forming a 3mm thick block, then I freehanded a rough shape of it onto the side of the block, carved away the extreme excess material with a sharp knife and then i started filing away until I found the shape being satisfactory.
To attach the barrel I Dremel\'d a \"hole\" in the forward part of the stock and then cut a satisfactory length of plastic pipe, filed it down so it fit the carved hole and glued it in place.
The trigger is a 0.6mm thick steel wire piece I filed down to make it \"flat\" and glued it into a drilled hole in the stock.
I made the guard from a cut length of thin brass from the \"sprue\" from the FW Imperial eagle set.
And the drum is as simple as this: I took an old sprue frame from GW and cut loose one of the large round \"buttons\" the have, filed a hole in it so it fit the pipe and filed a trace around the edge for looks.
After that it was just adding some brown stuff and the small detail.
The creases in the barrel were made with a engraving tool.