Dry firing can hurt some guns, to be safe I would purchase a "snap cap". It is the same size as the actual shell but is made of hard plastic/rubber, some are metal with a spring loaded "primer". They give resistance to your firing pin just like an actual primer and prevent possible damage. They are cheap and easy to find at any gun show, gun shop, or on the net. It is also safer, if the snap cap is chambered you know a live round is not. "Snapping In" or dry firing is an excellent way to eliminate flintching and to work on your sight picture, trigger control, and breath control this is a proven fact.