From July 1916 to July 1919, Wilkinson served with distinction as the head of the Experimental Section, Bureau of Ordnance, where he developed ordnance materials and devices, most notable being a noxious gas filler for shells and an "exceptionally satisfactory smoke screen".
Following that tour ashore-for which he received a letter of commendation-Wilkinson went to sea, first serving as gunnery officer in the battleship Kansas and later as fire control officer in .