A cam pin is an integral component of the bolt carrier group (BCG) in rifles like the AR-15, playing a critical role in the firearm's cycling and locking mechanism. It is a small, cylindrical pin with a flat head, typically made from hardened steel for durability. The cam pin fits through a hole in the bolt and engages with the cam track inside the bolt carrier. As the bolt carrier moves back and forth during the firing cycle, the cam pin rotates the bolt, enabling it to lock and unlock with the barrel extension. This rotation ensures a secure lockup of the bolt when firing, providing safe containment of the high pressures generated. Additionally, the cam pin ensures precise alignment of the firing pin and bolt during cycling. Proper lubrication and maintenance of the cam pin are essential to prevent wear and ensure the reliable operation of the bolt carrier group.