Which component of the 120mm mortar ensures the cannon is locked to the baseplate?

The component that ensures the cannon is locked to the baseplate is the clamp handle assembly. This assembly plays a critical role in securing the cannon to the baseplate, preventing any movement during firing and ensuring the stability of the mortar system. When properly engaged, the clamp handle assembly locks the cannon in place, allowing for accurate and repeatable firing. This is vital for maintaining the integrity of the mortar's aiming and firing capabilities.

In a functional mortar system, the other components, while essential for different operations, do not specifically serve the purpose of locking the cannon to the baseplate. For instance, the elevation handwheel is used to adjust the angle of elevation for targeting, and the cannon lock is involved in securing parts of the cannon during transport rather than linking it to the baseplate. The baseplate slot is a feature that facilitates the alignment of the cannon but does not itself secure the connection. Thus, the clamp handle assembly stands out as the key element for locking the cannon to the baseplate.