Saw a stock on a .22 sihouette rifle which had been made by carving out a foam core, then covering it with glass and resin. Ugly, but the rifle shot very well. There is even a book describing how to make moulds and stocks written by a gentleman in Ottawa. The moulds are made from plaster, using an existing stock as the pattern. I suspect that making a stock this way would help one appreciate the quality of commercial stocks, like the ones made by Ian Robertson.