[Webstral]

In a nutshell, the RPG HEAT round, like any High Explosive Anti-Tank round, exploits a phenomenon called the Monroe Effect to focus a portion of the energy of a chemical explosion into a pencil-thin armor penetrator sometimes called a plasma bolt. The shaped charge that generates the Monroe Effect incorporates an inverted cone, usually copper, surrounded by high explosives inside a casing like the exterior of an RPG round. When the explosive detonates, the inverted cone reverses its orientation, turning from concave (the point facing back towards the main body of the round) to convex (the point facing towards the target). The metal of the cone becomes super-heated and is focused by the Monroe Effect into a pencil-thin penetrator. Some speak of a plasma bolt burning through armor. Technically, this idea is not accurate. The penetrator acts more like a spike driven by a colossal pile driver. Pressure on the order of 100,000 atmospheres cause the penetrator to pierce the armor and liquefy it by sheer kinetic energy as the penetrator pushes forward. When the penetrator reaches the open cavity inside the crew compartment, the crew is exposed to an effect called spalling. The armor liquefied by the penetrator sprays across the interior of the crew compartment. Also, the penetrator becomes less focused and contributes to the spray of very high temperature material moving through the interior spaces of the target vehicle. At the very least, the crew will suffer injuries as a result of spalling, and equipment will be damaged. Spalling or the plasma bolt itself may strike ammunition or fuel, often resulting in what is euphemistically termed a catastrophic kill.

The penetrating power of a given HEAT round versus RHS (rolled homogenous steel) typically equals three times the diameter of the warhead. In cases in which the penetrating power of the HEAT warhead significantly overmatches the armor of the target, the penetrator might actually cross the interior space, penetrate the armor on the other side, and exit the target vehicle. This is a likely result of an RPG HEAT round striking the side armor of an M113. This is not to say that the passengers and crew won’t be KIA or WIA. Spalling will produce numerous injuries. Anyone actually struck by the plasma bolt will be killed or badly wounded. The plasma bolt may strike fuel, ammunition, or explosives inside the crew compartment. It’s unlikely, though, that the penetrator will fail to exit the vehicle, given the enormous penetrating power of an RPG HEAT round vis-à-vis the armor of an M113 or any other APC.