Originally Posted by mmande

One of the first things we teach new shooters in our clubs revolver league is to make sure the ammo is pressed tightly into the chamber. Weather rim fire or center fire there can be build up in the chamber and the round will not seat properly. When the firing pin first hits the round it merely seats it into the chamber because there isn't enough resistance to set the primer off. If it still doesn't go off on the second hit then you need to look into other causes of the misfire.
Just a thought;
Mike