A firing pin is a crucial component of the bolt carrier group (BCG) in firearms, specifically in rifles like the AR-15 and similar models. This slender metal rod is positioned within the bolt of the BCG and plays a vital role in the firearm's firing mechanism. When the shooter pulls the trigger, the hammer strikes the rear end of the firing pin, propelling its forward tip to impact the cartridge primer. This action ignites the primer, setting off the propellant and firing the bullet. The design and material of the firing pin are critical for ensuring reliable ignition while withstanding repeated impacts and the high pressures generated during firing. Some firing pins are hardened to prevent deformation or wear, while others are coated to resist corrosion and fouling. A well-functioning firing pin is essential for the consistent performance and safety of any firearm.