How to Calculate Sight Height

All hunters and shooters require precision accuracy to acquire a target. Part of accuracy is determining the correct sight position. Often, when a rifle's rear sight is changed, the front sight height will either need to be lowered or raised to accommodate for the arc of the bullet in order to produce a quality impact. This process requires a bit of target practice and a basic mathematical calculation after measuring the bullet impact on the target.

Things You'll Need

  • Target
  • Ruler
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Instructions

    • 1

      Set the target out at any preferred distance for sighting in your rifle. For this instruction, 100 yards is an ideal target distance for sighting in a rifle.

    • 2

      Fire a group of at least three shots from a stable shooting position. Note that the "prone" shooting position or shooting from a secure rest offers the most stable shooting positions.

    • 3

      Convert the yard range to inches. For example: A 100-yard range is multiplied by 36, this equals a 3600-inch range.

    • 4

      Measure the distance that the center of the shot group is from the center of the target bull's-eye in inches. Measure the distance between the front sight and the rear sight in inches. The distance between the front and rear sight is the sight radius.

    • 5

      Multiply the distance from center of shot group to center of bull's-eye by the sight radius. Divide the answer by the range distance in inches. For example: If the weapon shot 10 inches high at 100 yards and the sight radius of the weapon is 23 inches (common on most rifles). Ten inches multiplied by 23 inches equals 230 inches. Two hundred-thirty divided by 3600 inches equals .064 inches, or approximately 1/16 of an inch. The sight needs to be raised by .064 inches. If the weapon was shooting low, the sight would need to be shortened or lowered by .064 inches.