What is the primary use of the Upper Saddle?

The primary use of the Upper Saddle is indeed for boresighting. Boresighting is a critical procedure that involves aligning the weapon system's optical sight with the barrel's line of aim, ensuring that the projectiles will hit the intended target. The Upper Saddle plays a crucial role in achieving this alignment as it supports the elevation and windage adjustments required during the boresighting process.

The Upper Saddle's design allows for precise control to ensure proper sighting adjustments are made before firing begins, which is essential for maintaining accuracy in various operational scenarios. Boresighting must be performed correctly to ensure that subsequent fire missions result in effective target engagement with minimal deviation.