The AR-15 bolt is a critical component of the bolt carrier group (BCG), responsible for the core functions of feeding, chambering, locking, and extracting cartridges in the AR-15 rifle. Machined from high-strength steel, typically Carpenter 158 or 9310 steel, the bolt contains key features like locking lugs, an extractor, an ejector, and a cam pin slot. The locking lugs engage with the barrel extension to securely lock the bolt in place during firing, ensuring safe and efficient energy transfer. The extractor grabs onto the rim of the spent cartridge case, pulling it out of the chamber after firing, while the spring-loaded ejector expels the empty casing out of the ejection port. Additionally, the cam pin slot guides the bolt's rotation, facilitating the unlocking and locking sequence as the bolt carrier group moves back and forth. Bolts are often phosphate or nitride coated for corrosion resistance and durability. Together with the carrier and other components, the AR-15 bolt ensures smooth and reliable semi-automatic or fully automatic cycling, making it an essential part of the rifle's functionality.