explosively formed penetrator

An explosively formed penetrator (EFP), also known as an explosively formed projectile, a self-forging warhead, or a self-forging fragment, is a special type of shaped charge designed to penetrate armor effectively, from a much greater standoff range than standard shaped charges, which are more limited by standoff distance. As the name suggests, the effect of the explosive charge is to deform a metal plate into a slug or rod shape and accelerate it toward a target. They were first developed as oil well perforators by American oil companies in the 1930s, and were deployed as weapons in World War II. Design Difference from conventional shaped charges A conventional shaped charge generally has a conical metal liner that is forced by an explosive blast into a hypervelocity jet of superplastic metal able to penetrate thick armor and knock out vehicles. A disadvantage of this arrangement is that the jet of metal loses effectiveness the further it travels, as it breaks up into disconnected particles that drift out of alignment.