I went out and fired my S&W 9 MM Shield pistol. This is what happened: I shot approximately 80 rounds though the weapon. During the 80 rounds I fired the weapon it ejected the spent cartridge and reloaded the next round ok. But the weapon did not cock the striker. I had to eject the bullet that was in the chamber and load another shell in order to get the weapon to fire. What would keep this weapon from cocking the striker since it ejected the shell and loaded the next bullet properly?