Went through all this myself a year ago. I used isapon, made a cast out of polystyrene put it on the gunstock, some cling filim on the stock first put the cast on and filled it to the top and halfway down my shooting side an just an inch down the backside. Then took it out and sanded it to the hight and shape I wanted. Great job when finished and it is a snug if to the stock. Bit of spray paint and few screws and your dune. I'll sent in a picture later if anybody wants. Used if for a year and saved for a GRS stock, very very good I must say.