Draw a line along the side of the gunstock comb where you wish to make your cut. Use a pencil and a straightedge to ensure that the line is level. It’s best to cut small increments at a time, so make your line no greater than 1/4 inch from the top of the comb.
Score a shallow cut line in the wood of the stock along the drawn line on both sides of the comb with a utility knife. Make the scored line about 1/8 inch deep to provide you with a good start for making the actual cut through the stock.
Cut through the gunstock along the scored line with a fine kerf razor saw. The combination of scored line and saw will get you through the wood without splintering the stock in the process.
Check the fit of the comb by firing a few rounds. If you can rest your cheekbone against the comb, and it no longer strikes your cheekbone with each shot, then it’s the proper height. Sand the comb smooth along the cutline with a piece of fine-grit sandpaper, or file the comb into a tapered or curved shape before sanding it smooth.