In 1921, he was transferred to the Ordnance Corps and subsequently served on various military posts across United States. Between 1931 and 1937, Sayler served as a member of the Cavalry Board. Sayler also attended the Command and General Staff College at Fort Leavenworth, Kansas in 1931.[2]
In 1937, he was appointed a chief of General Supply Division in the Office of the Chief of Ordnance and served in this capacity until the end of next year, when he was assigned to the 4th Corps Area as its ordnance officer. Then he was appointed an ordnance officer of the First Army under the command of Lieutenant General Hugh Aloysius Drum.[3]
During D-Day invasion he solved many problems, including waterproofing of vehicles and disposing bombs which didn't explode. Due to his great work at that time, U.S. Forces was one of the best-equipped fighting forces in the history of warfare.[5] Sayler stayed in this capacity until August 1945, when he was appointed an Assistant Chief of Ordnance, deputy of lieutenant general, Levin H. Campbell, Jr.