The Buckingham bullet (Mk VII bullet) was an incendiary/tracer bullet based on phosphor, invented by James Buckingham in 1914. The bullet contained an incendiary filling which percolated through an annular hole, the seal of which melted on firing, the phosphorus igniting on contact with the air.

BBC - h2g2 - Fighting the Zeppelin

Used in WW1 to shoot down Zepplins.
Have I done your homework for you?

__________________