While the 991st was Active, it was one of a few ARTY Bn's in World War Two to use GFP's. The Battalion had 155mm (SP) Tracked Howizters. Ammunition was exceedingly scarce at that time and the battalion conducted an experiment for First Army which enabled captured German ammunition to be fired. Tests fired by Batteries A and B proved that 15.5 cm German ammunition could be fired safely and subsequently the battalion was issued large amounts of it. It was the first time during the war that captured ammunition was fired out of American guns (OCT 1944).
