Bullet drop is the loss of elevation by a bullet that results from gravitational effects on a bullet when freed from the bore. Bullet projectile drop is the vertical distance between the projectile and the line of departure, or LOD.
A bullet starts dropping from LOD immediately as it leaves the muzzle. The downrange movement of a bullet occurs even with downward or upward tilting of LOD. Due to this drop, a bullet fired at zero elevation cannot hit its target. The magnitude of bullet drop varies among round nose, Spitzer and flat nose bullets. Bullet drop compensators help manage bullet drop by providing elevation turrets that show the proper yards to target.