The long-range 3.7s were used for a long programme of counter-battery (CB), Interdiction and HF tasks, with half the guns capable of immediate reversion to the AA role if enemy aircraft appeared. One 3.7-inch HAA gun, detached to 16th Field Rgt with 2nd Division, could just reach Mandalay. 20th Indian Division began its crossing on 12 February 1945, supported by a corps fire programme including 'bombard' tasks from 3-7-inch guns at using AA Fuzes. It took 20th Indian Division two weeks to establish a firm bridgehead and beat off counter-attacks, then 2nd Division began its assault upstream, supported by the Corps artillery in similar fashion. By the first week in March, XXXIII Corps' divisions were closing in to capture Mandalay from several directions, and 101st HAA Rgt's batteries were once more decentralised to the divisions, moving and fighting with the infantry, often under heavy shellfire. 19th Indian Division reached the outskirts of the city on 7 March and began a siege of Fort Dufferin. After that citadel fell on 20 March, 2nd and 20th Indian Divisions began to clear the city. Now that the Irrawaddy was crossed and Mandalay captured, the country was more open, and Fourteenth Army could drive towards Rangoon. 101st HAA Regiment remained as Corps HAA regiment with XXXIII Corps, used mainly in the ground role, though 297 and 379 HAA Btys were posted to defend Magwe airfield when it fell to 19th Indian Division on 19 April (XXXIII Corps was depending on supply by air). During the advance on Prome, gunners of 101st HAA Rgt fought for a while as infantry, guarding the gap between XXXIII and IV Corps. They sent out fighting patrols and fought several actions with Japanese troops trying to escape eastwards. The regiment was then concentrated at Allanmyo for rest before returning to ground and air defence artillery tasks. By 20 May, 101st HAA Rgt was supporting 268th Indian Infantry Brigade in its advance along the east bank of the Irrawaddy. The weather broke and made all movement difficult, but opposition was light, and the force established a cordon along the river to catch the retreating Japanese, who made determined attempts to break through until the fighting ended on 30 May. June was spent clearing up pockets of Japanese in the Irrawaddy area. In June 1945, XXXIII Indian Corps was disbanded (its HQ became the basis for the new Twelfth Army) and the AA organisation in Burma was regrouped.