What is the automatic HOB correction for the time portion of precision registration if the first round is a graze burst?

The automatic Height of Burst (HOB) correction for the time portion of precision registration when the first round is a graze burst is set to "Up 40." This adjustment is necessary because a graze burst typically occurs at a lower altitude, meaning that the projectile does not have a sufficient altitude for an effective burst at the desired height. To achieve the desired effect, a 40-meter increase in the burst height is required. This ensures that the explosion reaches a higher elevation, enhancing its effectiveness against the target. Understanding this principle is crucial for effective artillery operations, where precise timing and height of burst can significantly impact the accuracy and lethality of fire support.