4-inch Blacker Bombard spent cartridge, 1940 (c)

The Blacker Bombard was invented in 1940 when Britain was under threat of German invasion. It was designed for the Home Guard at a time when the nation was short of equipment.

Unlike conventional mortars that consisted of a tube, the Blacker Bombard was basically a steel rod fixed to a base plate. Its projectiles had charges inside their tails. These were pushed down onto the rod, which exploded the propellant and fired the projectile.