1. A method of programming a trigger time of a projectile, the method comprising: determining a muzzle velocity of a projectile after it exits from an associated gun barrel; determining an flight speed of the projectile a predetermined time after it has been fired; and accounting for the deviation of the projectile's muzzle velocity and flight speed from those determined by an associated ballistic computer and programming the trigger time during the remaining flight time as the projectile is reaching its target, thereby optimizing the effectiveness of the projectile.