Since the existing buttstock probably is not flat at the butt, you can cast a black spacer to make a flat surface to work on without destroying the butt grooves or checkering. Stretch Saran Wrap over the butt and tape it down on the side of the stock securely . Then use masking tape or similar to form an edge around the butt, making sort of a dam. Black epoxy, or similar, can be poured as thick as needed and it will conform to the existing butt and you can shape a flat surface on the other end. Then apply your pad material. I have seen this same thing done using the epoxy to form a full thickness extension . It doesn't look too bad and the original butt will be saved.
Excellent idea! This may be a future project for me to try.
