On 1 September Buckley’s battalion was involved in operations aimed at clearing the area between Mont St Quentin and Peronne. The advance commenced in drizzling rain and was opposed by heavy fire. The first line of enemy trenches was taken but the advance was held up by a nest of machine gunners. Buckley with another man rushed the post, shooting four men and taking twenty-two prisoners. The Germans retreated to Peronne, entering the city by the main bridge which they then destroyed. The only remaining bridge on the battalion's front was a footbridge defended by machine guns. With three other members of his company, Buckley tried to force his way across under heavy fire. He was killed in the attempt.