CHIEF MORRIS GIVES A FIELD ARTILLERY DEMONSTRATION. Video 2 The Field Artillery is one of the Army's combat arms, traditionally one of the three major branches (with Infantry and Armor). It refers to those units that use artillery weapons systems to deliver surface-to-surface long range indirect fire. Indirect fire means that the projectile does not follow the line of sight to the target. The term field artillery is to distinguish from the Air Defense Artillery, and historically, from the U.S. A