Made to order recoil pads simply do not fit walnut stocked rifles. Remington has had some success using the pre-fit pads on synthetic stocked guns where they can better control the stock dimensions.
You will have to buy a new pad and grind it to fit. One trick I recently discovered to get super close is to get within .050" with the belt sander, then use aluminum tape to lay one layer on the stock right up to the pad. Using a sanding block with 150 grit sand paper, you can maintain your toe and comb lines and get an extremely close fit without dinging your stock finish. Finish up by removing the pad and using 220 paper to take the base down another .020" or so. The 220 will give you a nice smooth finish and a bit of lemon oil at the end will make it beautiful.
Don't forget to use a razor blade to slit the pad holes and then a smooth screwdriver bit with some wax to keep from tearing the holes in the pad.
