Zero In

(zîr′ō, zē′rō)

(Firearms, Gunnery, Ordnance & Artillery) a gunsight setting in which accurate allowance has been made for both windage and elevation for a specified range. The act of setting up a telescopic or other sighting system so that the point of impact of a bullet matches the sights at a specified distance.

Zero in a Sight Zero in a Sight