What is the purpose of the elevation locking knob in the M67 Sight Unit?

The elevation locking knob in the M67 Sight Unit serves the specific function of locking the elevation setting in place. This feature is crucial for maintaining a consistent sight picture and ensuring that once the desired elevation has been set, it does not accidentally change during operation. By locking the elevation, the gunner can engage targets with confidence, knowing that the adjustments made will remain effective throughout use, even during movement or recoil.

While other functions such as adjusting deflection, calibrating the sight, or switching between elevation scales are important in their own right, they do not pertain directly to the role of the elevation locking knob. The focus here is on securing the elevation adjustment, which is critical for accuracy in targeting.