On 1 June 1925, McClellan was transferred to the Marine Barracks at Pearl Harbor, in Hawaii, and took Manookian with him. McClellan departed Hawaii 15 November 1927, when he briefly toured the Western Recruiting Region. On 19 October 1928 he joined the 5th Marine Regiment to serve as a photographer of the occupation of Nicaragua until 24 July of the next year. After a brief stop in Quantico to attend the Field Officer’s Course, he returned to direct the Historical Section again on 20 June 1930. During this second tour, he compiled a seven-volume history of the Corps, but the Great Depression made printing unfeasible, to which he resorted to hand-mimeographed copies for distribution.