Actually it is the pin in the center of the cylinder that is pushed with the thump piece to unlock the front of the cylinder.
It is too soft and heavy recoil will peen it. It is inertia. One reason to not shoot heavy bullets.
The pin is in the center of the extracting rod.
The only way to open the gun is by using a hunk of wood on the thumb piece and tapping it. Then you must remove the cylinder and take it apart to get to the pin. LEFT HAND THREAD on the extractor rod.
