Is it a really nice stock already? Is it stained nad lacquered or oil finished?
I would use a spray paint to cover it smoothly and evenly and let it dry well and then I would apply several coats of polyacrylic. The poly is chemical and solvent resistant and will give you a nice finish. It comes in satin and clear and maybe another finish. depending on what you are crawling therough, the stock will scratch. If you want a no-nonsence finish, get a composite stock.