A revised version of Field Manual 18–5, introduced in June 1944, broadened the doctrine of tank destroyer operations. It allowed for a more dispersed deployment of the battalions throughout a force, and recommended that when enemy armor was only expected to be deployed in small groups, tank destroyers were to be distributed among forward units. It became general practice to attach a tank destroyer battalion semi-permanently to a division; this meant that it was locally available for emergencies, and that it would be able to train alongside "its" division when out of the line.