Firearms are constantly subjected to regulations and legislation in attempts to control access and limit operation only to authorized users. Many efforts have been made to track the critical components of a firearm throughout its operating lifetime, with one of the most critical firearm components referred to as the receiver. The receiver contains the trigger and the bolt. The receiver is often the only portion of a firearm that’s federally regulated and required to be serialized.
Recent development of miniature, mechanically robust radio-frequency-identification (RFID) tags provides the means of tracking firearms and their receivers in difficult environments. To demonstrate this new capability, small RFID tags will be used to track the lower receivers in AR-15 family firearms for smart gun applications.
The AR-15 lower receiver (LR) has been chosen initially for a number of reasons. It’s the only component in the rifle that requires federal regulation and is serialized, making it the prime candidate for tracking. The LR being the main mechanism of the rifle also requires a significant level of routine maintenance, which makes it ideal for automated RFID tracking applications.
Additionally, this family of semiautomatic rifles is one of the broadest and most popular in the world (automatic versions include the M4 and M16). Since each RFID tag incorporates an integrated circuit (IC) with an unalterable unique identification number (UID), it provides tracking by association with the federally regulated serial number of the component. The unalterable functionality is a requirement of currently proposed new legislation (NJ Bill A1016, which also mentions the use of RFID).
By means of RFID, the receiver is well-suited to act as the “custodian” of a firearm’s history by recording within an RFIC tag’s IC any pertinent information of any components that are part of the assembly. Information can be stored within any RFID IC that also contains programmable memory in addition to its UID. The storage of information occurs within the RFID tag, whose IC also has a programmable memory in addition to its UID.
Furthermore, the UID has the functionality to track/identify the original serial number of the receiver, making it possible to identify firearms when the serial numbers are removed. The RFID IC’s programmable functionality can also be locked, making it unalterable if required.
Figures 1 and 2 provide a number of different views of an AR-15 LR. They are typically forged from a lightweight aluminum alloy (7075-T6), but can also be made from steel or a composite material. This current study has focused on metal receivers, since they are more common and more challenging in terms of performing tracking by means of RFID technology.