Second, short and vague hand-wavy descriptions are not going to cut it. There's no description of where these trackers would go. There isn't a lot of empty space inside a gun; places where this might go are inside pistol grips or at the bottom of magazine wells, but those are both easily accessible. Furthermore, anywhere these trackers go would have to be accessible. Otherwise, how do you replace the batteries?
It would be challenging to design circuitry relying on solder that would stand up to the shock of being attached to a gun that's fired dozens or hundreds of times at a range, or thousands or tens of thousands of times over a typical gun's lifetime.
What does your tracking system accomplish? Guns that are stolen are going to be checked for GPS and NFC trackers, which will be removed or disabled. Guns that are bought legally (Cho) for use illegally (VA Tech) are going to have the GPS and NFC trackers removed or disabled, too.