In the scenario you described, with a prone sniper in a long rectangle-shaped hallway and adjustments made for optics and force, the target's Z-axis location can indeed impact accuracy. Let's examine how the point of perpendicularity, or the point where the bullet trajectory intersects the target, can be affected.
Gravity and bullet trajectory: When a bullet is fired, it follows a parabolic trajectory influenced by gravity. Gravity acts vertically downward, causing the bullet's path to curve downward as it travels. This means that over longer distances, the bullet will drop more due to the effect of gravity.
Zeroing the rifle: Zeroing a rifle involves adjusting the sights or optics so that the point of aim coincides with the point of impact at a specific distance. Typically, rifles are zeroed at a certain distance, such as 100 yards/meters. This means that if the target is located at the zeroed distance, the bullet trajectory will intersect the point of aim (crosshairs) at that distance.
Impact of Z-axis location: If the target's Z-axis location, which represents the vertical position or height, is different from the zeroed distance, the bullet trajectory will not intersect the point of aim at that specific height. For example, if the target is located higher or lower than the zeroed distance, the bullet will either impact higher or lower than the point of aim, respectively.
Point of perpendicularity: The point of perpendicularity refers to the distance at which the bullet trajectory aligns with the point of aim, resulting in the bullet hitting the target at the intended point. This point is typically the zeroed distance. However, when the target's Z-axis location is different, the point of perpendicularity shifts accordingly.
When the target is located higher than the zeroed distance, the point of perpendicularity shifts to a closer distance, as the bullet will drop less due to gravity before reaching the target. Conversely, when the target is located lower than the zeroed distance, the point of perpendicularity shifts to a farther distance since the bullet will drop more before reaching the target.
To maintain accuracy in such scenarios, the sniper would need to make adjustments to compensate for the difference in the target's Z-axis location. This could involve aiming higher or lower to ensure the bullet trajectory intersects the target at the desired point.
It's worth noting that other factors, such as wind, air resistance, and the bullet's ballistic characteristics, can also affect accuracy and would need to be considered in real-world shooting situations.