There are several variations for applying artillery (and mortar and naval gun) fire for suppressive effect. In World War I a moving barrage was the normal method; shrapnel shells were fired to place their bullet cone ahead of the advancing infantry with their aimpoints moved 100 yard further forward every few minutes on a front of several kilometres to support an attack by several divisions or corps. High Explosive (HE) barrages were also used in World War II, including to cover the advance of tanks by suppressing anti-tank gunners.