On 19 June 39th Siege Bty was back 'in action' north of Arras. 30th Brigade was now under First Army and remained with it until the end of the war. The summer was spent on HF and counter-battery (CB) fire tasks. The Allied Hundred Days Offensive began on 8 August and First Army began to advance on 18 August, supported by CB fire. On 19 September the heavy guns began moving forward to support First Army in the Battle of the Canal du Nord on 27 September. During October 39th Siege Bty moved up again, reaching Billy-Montigny with five of its howitzers on 13 October, but on 18 October it had to be left behind because there was no canal bridge strong enough to take its heavy howitzers. It finally moved up on 1 November, and four of its howitzers came into action on 4 and 5 November, but the Germans were retreating too quickly for the howitzers to keep up. Hostilities ended on 11 November when the Armistice came into effect.