In simple terms, offset refers to the distance between a firearm’s sights and the bore of the barrel. Since the sights or optics sit above the bore, it is necessary to factor in offset. For example, if a shooter is looking through a red dot optic mounted to an AR-15 and shooting at a 10-yard target, the round will typically impact below the point of the dot. Shooters will have to factor in this offset—sometimes anywhere between one inch and three inches— when engaging targets at certain distances, and the offset can be different between different rifles, optics, and mounting methods. Handguns also have a small offset, but there is usually a minimal difference between the point of aim and the point of impact, even at very close ranges, unless the handgun has a red dot optic.