What component interacts with the barrel extension to lock the bolt with the barrel?

The correct answer is the locking block, which is a critical component in the functioning of a firearm's action. The locking block is designed to interact with the barrel extension by securing the bolt in place during the firing process. When the bolt is locked into the barrel extension, it ensures that both components are aligned properly, which is essential for achieving consistent accuracy and preventing any premature unlocking during the firing cycle.

This mechanical connection is crucial for maintaining the integrity of the firearm when it fires, as it manages the high pressures generated within the chamber. The locking block typically moves into place as the bolt is rotated or moved forward, effectively locking the two components together until the cartridge has been fired and the action has completed its cycling.

Understanding the function of the locking block is vital for anyone involved in firearms maintenance and troubleshooting, as it helps in diagnosing issues related to feeding, extraction, and overall reliability of the firearm.