The shaped charge: destroyer of tanks.

The idea of the shaped charge came about in the late 1700s as a mining application. By today's standards these early charges were rather ineffective and underdeveloped. It wasn't until the Second World War that the shaped charge came into its own.

What is a shaped charge? It's an explosive that is shaped in such a way that its explosive force is focused onto a single point. The standard shape is conical in nature. Modern shaped charges have a metal lining on the face of the explosive, often copper or steel, which acts as the penetrator.  When it explodes, the charge does not melt or burn through the armor but rather creates a focused stream that moves at hypersonic velocity and turns the lining metal into a dense penetrator, cutting into the steel armor via kinetic energy and punching through it.

The photos below show an M9 anti-tank rifle grenade and its effect on armor.

The first photo shows four different situations with their resulting effects. From left to right: (1.)An unshaped charge, when placed directly against the armor, has almost no effect on the armor; (2.) an underdeveloped shaped charge, when placed directly against the armor, has a mediocre effect on the armor; (3.)a well developed and correctly shaped charge, when placed directly against the armor, has good effect on the armor; (4.)and finally, a well developed and correctly shaped charge, when given the right amount of standoff, produces the maximum amount of armor penetration.

The next three photos show an M9 rifle grenade from my collection. The rounded nose piece is empty: it gives the shaped charge proper standoff to allow for maximum penetration. When the nose piece is removed, we can see the copper liner cone behind which the explosive would normally be. This specific rifle grenade is inert.

When the grenade is fired and hits the target, the deceleration forces the striker pin, which is behind the explosives in the tail of the grenade, to move forward and strike the primer, setting off the explosives. This process along with the explosion all happens in a milli-second.

Shaped charges were used during WW2 in rifle grenades, bazooka rockets, tank cannon rounds, and magnetic mines by numerous combatants including the U.S. Army. They were an effective means by which heavily armoured vehicles were knocked out.