It should be noted that a doll's head without a bite (Last such I saw was on a Jeffery 450-400) does serve to help keep the action closed on firing. It does nothing to prevent opening the action to load and at first glance one would think the same thing would apply on firing. How ever the forces are subtly different in their action and the center of rotation for the doll's head at firing is not the hinge pin. I've a diagram of this someplace, wish I had it here. Of course this assumes proper fitting.