gunnut has good advice. Here is another method to fill pores/grain. I prefer to use some form of antique oil or Danish oil and coat the wood well with it, letting it soak in for a minute or so. Generally, I would wet down, lets say, one side of the butt stock. Then while still wet, not tacky, use a fine wet type sandpaper (320-400 grit) and sand wetted area with the grain. This produces what is sometimes called a surry which helps fill the pores/grain. Then while wood still wet (not tacky), use a lint free cloth and wipe off excess, once again wipeing with the grain. I normally use cloth from an old T-shirt for this. I then repeat this process till I've worked all the stock. I may do the entire stock again using a finer grit paper or at least do a very light sanding (with grain again) using 000 steel wool or 500-600 grit paper. You can use then use a product of your choice for a final coat.....I generally use a wiping polyurethane, like Minwaxs, and apply several coats using it.