shaped charge munitions

Cylindrical charge of explosive which has one end hollowed out into a cone or hemisphere and lined with metal or glass. When the explosive is detonated from the other end, the advancing detonation wave collapses the liner into a jet of molten metal and explosive gas moving at very high velocity. The momentum of this jet will penetrate armour plate or other hard targets.

Although the phenomenon was known in the 1880s it was not until the late 1930s that it was put to any practical use, and from 1940 all combatants developed shaped charge artillery shells, grenades, bombs, and rocket warheads to defeat tanks and reinforced concrete defences.