Lee's gun possesses some peculiar characteristics. First, it has a barrel of not more than three inches long. Second, it's claimed to be "invisible" to metal detectors. Third, Sarah discovers the gun's shells which appear to be 12-gauge as for a shotgun or flares pistol. It can be concluded that the gun is made of nonmetallic composites, meant for very close range (as for an assassin), and is chambered for shotgun shells (the "22" on the data sheet representing a model number rather than a caliber).