In the Season 5 episode "The Beta Test Initiation" Leonard takes Penny to a shooting range for a date. Penny is seen picking up the hangun, pulling the slide back, letting it slide forward, then loading the magazine into the gun. She then hands the gun to Leonard who promptly shoots himself in the foot when Penny kisses him. However, this would be impossible since there was no round ("bullet") in the chamber. In order to load a semi-automatic handgun, a loaded magazine must first be placed into the gun, THEN the slide is cycled. Cycling the slide prior to inserting the magazing (as Penny did here) does basically nothing.