When you go too fine with the paper, you can wind up actually burnishing the wood, and just pushing the sanding dust in to the pores, You're going to be wetting it and de-whiskering it anyway. Most people don't advocate going much finer than that (220-320) or that phase. It's going to be covered with some kind of a finish as well. If you want a silky smooth perfect finish (like on a Best Quality London-made gun, like a Holland and Holland Royal) , THAT is the time to go super fine with the sandpaper, or finishing compounds. Those guys go down t about 2000 grit or use rottenstone then. That sort of a finish isn't really appropriate for a "period" American gun though.