Self-forging warheads are used whenever a weapon of necessarily small size must try to penetrate armor
. It is, essentially, a way to create a kinetic penetrator
out of a shaped charge, without having to move it a great distance. A block of high explosive
is formed with a cavity on one side (the side that reads FRONT TOWARDS ENEMY
). This cavity is the basis for a shaped charge
; when the explosive is detonated
, the hot gases that result will converge in the cavity and rush outwards along its vertical axis with great force.
However, modern armor (such as used on main battle tanks) is capable of defeating the blast from a small shaped charge. In order to increase these smaller weapons' chances of penetrating the armor, the cavity can be lined with copper or another malleable but reasonably dense metal. When the explosive detonates, the cavity (usually somewhat parabolic) pushes all the thin copper sheeting together at one point, forming a fairly dense mass, which is then pushed outward towards the target with great force by the explosion. By changing the shape of the cavity and the metallic liner, various penetrator shapes can be formed. The variation isn't terribly significant, however, as the copper is a plasma by the time it leaves its cavity.
One example of a system that uses this form of warhead is a small submunition designed to detonate over, and attack the top of, the aforementioned MBTs. Another is less high-tech; Global Security reports that IEDs in Iraq have been found (some the hard way) which exploit this effect to defeat the armor on Coalition vehicles. While not as effective as carefully-manufactured versions, a crudely fashioned cavity in explosive blocks lined with a malleable metal such as aluminum or copper is still noticeably more effective than simple high explosive.