Second Zero

Because a bullet leaves the bore on a slightly upward line and then falls under gravity, its trajectory crosses the line of sight twice, and the second zero is the farther of those two crossings. After the near crossing the bullet rises above the sight line, crests, and descends back through it at the second zero, which is the distance most shooters mean when they state a rifle’s zero. Past this point the bullet falls steadily below the aiming line and requires holdover or dialed elevation.

The relationship between the near and far crossings is what makes a single sight setting useful across a span of distances. Choosing the second zero distance carefully, together with the height the bullet reaches in between, defines the rifle’s point-blank range. Shooters who understand both crossings can place a zero that keeps the bullet within a small vertical window over a long stretch of ground.