POWERED FASTENER DRIVER

A pneumatic fastener driver operable in a single sequential mode and a bump-fire mode, and includes a housing, a nosepiece, a trigger moveable between a default position and a depressed position, a contact arm movable relative to the nosepiece between an extended position and a retracted position, and a timeout mechanism operable in the bump-fire mode to inhibit the drive cycle from being initiated in response to inactivity of the contact arm over a preset time interval defined by unwinding of a mainspring that is initially wound in response to the trigger being actuated from the default position to the depressed position. The pneumatic fastener driver also includes a counting assembly having a female barrel pivotably coupled to a pivot shaft of the trigger and driven by the mainspring and a lockout linkage coupled to the female barrel that is capable of interfering with a portion of the trigger.