Silicone shouldn't hurt your stock's finish, but it will make it slick. If you use the silicone cloth to wipe down the wood before putting the gun away, be sure to wipe it off with a dry rag before firing the gun or else your hands could slip on the slick surface. Oil, of course, can make the stock slick also. This is one of the reasons I like to wear gloves while shooting. Gloves greatly increase the resistance to slipping of your hands on the stock.