Following his transfer to the Ordnance Corps as a first lieutenant in October 1898, Williams spent a short time at Rock Island Arsenal and, then, inspected gunpowder for three years at the DuPont Powder Works in Wilmington, Delaware.

As a major, Williams served four years from December 1907 until January 1912 as a member of the Joint Army-Navy Board to Formulate Specifications for Gun Forgings, followed by six months in 1912 inspecting ordnance materiel in England.

[1] Returning to the United States as the commanding officer at Watertown Arsenal, he again traveled to Europe at the end of 1914 as American military observer with the German Army for six months.

During the closing months of World War I, he improved the organization of the Ordnance Department to increase efficiency and decentralize the procurement process to avoid delays.

He oversaw improvements in coast defense armament and ammunition, and directed that work begin on a semiautomatic rifle, which would prove so beneficial in World War II.