In preparation for the St. Mihiel Offensive, the regiment moved into forward gun positions constructed with the assistance of the division's infantry. Beginning at 0100hrs on 12 September 1918, the 320th participated in a four-hour preparation, consisting of counter-battery fires on 16 German batteries and other positions. After the offensive started, the regiment also fired on "fugitive targets". On 13 September, the 320th and its sister 321st Field Artillery fired 10000 rounds in support of a raid by the 327th Infantry in the Bois Frehaut. The result of the St. Mihiel operation was "the establishment of confidence, born of performance" throughout the 157th Brigade.&lt;br&gt;