What is the purpose of the white line (skunk line) on the 120 mortar?

The white line, often referred to as the "skunk line," on the 120 mortar serves a crucial function by aligning with the firing pin. This alignment is essential during the loading process to ensure that the mortar round is oriented correctly for firing. Proper alignment helps achieve the accuracy and effectiveness needed in mortar operations, especially regarding the trajectory and target engagement.

In contrast, the other choices pertain to different aspects of mortar operation and control. The elevation indicator is separate and serves to establish the proper angle for the mortar's trajectory, while calculating distance generally involves calculations based on the mortar's settings and the target's distance, not indicated by a line. Similarly, wind adjustments are made using a different set of procedures and considerations, relying on data rather than a physical mark on the mortar itself. Therefore, the primary purpose of the skunk line is to ensure precise alignment with the firing pin, which is vital for successful mortar operations.