What does it mean to "zero" a rifle?

"Zeroing" a rifle refers to the process of adjusting the sights so that the point of aim and the point of impact coincide at a specific distance. This adjustment ensures that when a shooter aims at a target, the bullet hits where the sights are aligned. Properly zeroing a rifle is crucial for accuracy, as it compensates for factors such as bullet drop and windage that can affect where the bullet lands.

The other options, while related to rifle use and maintenance, do not accurately define the concept of "zeroing." Selecting appropriate caliber ammunition ensures proper function and safety but does not involve sight adjustments. Cleaning the rifle is important for maintenance and performance but also does not relate to sight alignment. Setting the magazine capacity pertains to the capacity of the magazine and how many rounds it can hold, which is unrelated to aiming and accuracy. Thus, adjusting the sights for accurate aiming is the correct understanding of "zeroing" a rifle.