Which part must be functioning properly for the locking mechanism to engage during firing?

The cylinder bolt plays a critical role in ensuring that the locking mechanism of a firearm, particularly in revolvers, engages properly during firing. It is responsible for securing the cylinder in place when the firearm is cocked, preventing it from rotating until the trigger is fully pulled. For a firearm to function correctly, the cylinder bolt must effectively lock the cylinder at the correct alignment with the barrel, allowing for safe and accurate firing.

If the cylinder bolt is malfunctioning, it may fail to engage properly, leading to potential misfires, misalignment, or even dangerous situations where the cylinder could rotate unexpectedly when the hammer falls. Therefore, the proper functioning of the cylinder bolt is essential for the locking mechanism to operate safely during the firing process.