Originally Posted by bushveld
cock the hammers/tumblers. you released them (pulled the triggers) while you had the barrels off the action.

Given that the original poster can't get the shotgun to close in the first place in order to recock the hammers, is this done by pushing the receiver's cocking dogs (or whatever they're properly called) against the edge of a workbench or kitchen table, or something? (I seem to recall a Midway video wherein their ancient British gunsmith did just that.)