Just curious, why would you want to open a cocked hammergun?
I do it occasionally. I get ready to shoot a clay, barrels loaded, hammers cocked and step on the trigger for the thrower and get a busted bird on the thrower that needs to be cleared. Open the action (hammers still cocked) lay the gun on the endgate, fix the thrower, then pick up the gun, close the action and go again.
All hammerguns should be opened on half cock only. Not full cock. It is a safety issue.
Many (most?) hammer guns with rebounding hammers don't HAVE a half cock position.
