M69 incendiary M69 incendiary The M69 incendiary bomblet was used in air raids on Japan and China during World War II. They were nicknamed "Tokyo calling cards". The M69 was a plain steel pipe with a hexagonal cross section in diameter and long. It weighed about . The bomblet used napalm (jelled gasoline) as an incendiary filler, improving on earlier designs which used thermite or magnesium fillers that burned more intensely, but were less energy- and weight-efficient, and were easier to extinguish. In Germany they were filled with jellied oil and dropped in clusters of 36 in the non-aerodynamic M19 bomb. Over
Incendiary ammunition night fighters for use against military zeppelins threatening the British Isles. The flammable hydrogen gas of the zeppelins made incendiary bullets much more deadly than standard ones which would pass through the outer skin without igniting the gas. Similarly, incendiary ammunition was used against non-rigid observation balloons. The British Royal Flying Corps forbade the use of incendiary ammunition for air-to-air combat with another airplane, as their use against personnel was at first considered to be a violation of the St. Petersburg Declaration. Pilots were permitted to deploy them against only zeppelins and balloons, and they were additionally restricted to shooting