High Quality Content by WIKIPEDIA articles! This is a list of U.S. Army fire control, and sighting material by supply catalog designation, or Standard Nomenclature List (SNL) group "F". The U.S Army Ordnance Corps Supply Catalog used an alpha-numeric nomenclature system from about the mid 1920s to about 1958. These designations represent parts catalogs for supply and repair purposes. There can be numerous volumes, changes, and updates under each designation