British cordite propellant (when uncased and exposed in the silk bag) tended to burn violently, causing uncontrollable "flash fires" when ignited by nearby shell hits. In 1945, a test was conducted by the U.S.N. Bureau of Ordnance (Bulletin of Ordnance Information, No.245, pp. 54–60) testing the sensitivity of cordite to then-current U.S. Naval propellant powders against a measurable and repeatable flash source. It found that cordite would ignite at 530 mm/22" from the flash, the current U.S. powder at 120 mm, /5", and the U.S. flashless powder at 25 mm./1"/