This is just a sugestion but you could remove the splintered wood and fill it in with Plastic Wood. You can get it in different colors and it can be stained. You probably will have to re-stain the whole stock if you want it to match completely. I have used the Tru-Oil stock finish and it is easy to use and, using multiple coats, you can sand it to the amount of shine that you like. It comes as a liquid, you can literally apply it with your fingers or a rag, and it also comes as a spray. It's the easiest finish I have ever used.