Abstract: The invention comprises a system for facilitating the locking of a firearm to prevent its unauthorized firing. The system provides an easily noticeable flagging device to facilitate visual affirmation that a firearm lock is engaged; and the firearm cannot be discharged until it has been unlocked. The locking system utilizes a locking wedge that activates a set of locking spurs so as to engage the interior of the firearm and disable the firing mechanism. The system provides for quick and simple enabling of the firearm to facilitate a quick response in an emergency. The system makes use of a locking device that can be inserted or extracted through the barrel of a firearm using a key rod. The locking device is not readily apparent or accessible externally to an observer. The system may be used to lock a firearm that is either loaded or empty, although it is obviously preferable and a proper precuation to apply the system only to empty firearms.