Firearm having inertially responsive safety mechanism

In a multi-barrel handgun having a frame, a barrel assembly supported on the frame and including a plurality of bores, each of the bores having an associated cartridge chamber, a hammer assembly supported on the frame for movement between tripping and striking positions and including a hammer, a firing element journalled for indexible axial rotation on the hammer, and means for retaining the firing element in assembly with the hammer, first biasing means for normally urging the hammer assembly toward its striking position, a trigger supported on the frame for movement between ready and firing positions, means for moving the hammer from its striking position to its tripping position and releasing it in its tripping position in response to movement of the trigger from its ready to its firing position, and means for indexing the firing element to align it in firing relation to a cartridge seated in an associated one of the chambers in response to movement of the trigger toward its firing position, the improvement comprising an inertia responsive safety mechanism including a blocking element, means supporting said blocking element for movement between inactive and active positions, said blocking element in its active position being disposed in blocking relation to said hammer assembly to prevent movement of said hammer assembly from its striking to its tripping position, means normally biasing said blocking element to its inactive position, and means for moving said blocking element from its inactive to its active position in response to inertial force acting on the gun and tending to move said hammer toward its tripping position.