What Is HEAT Ammunition? Shaped Charge Explained

# What Is HEAT Ammunition? Shaped Charge Explained

Quick answer: HEAT (High-Explosive Anti-Tank) is a warhead that uses a shaped explosive charge to focus energy into a needle-thin jet of molten copper traveling at 7,000–10,000 m/s (Mach 25). This jet punches through tank armor like a hot iron through butter.

HEAT is used in RPGs, ATGMs (anti-tank guided missiles), tank guns, and rifle grenades.

The Shaped Charge — The Genius Idea

A normal explosion pushes equally in all directions. But if you mold the explosive into a cone shape with a metal liner, almost all the energy gets focused forward into a thin jet of metal.

This is called the Munroe Effect (discovered 1888) or Neumann Effect.

Anatomy of a HEAT Warhead

Part	What It Does
Stand-off (nose cap)	Air-filled cone — gives the jet space to form
Detonator (rear)	Fires the explosive from the back
Explosive	Usually composition B or octol — high-detonation-velocity
Metal liner	Conical (typically copper) — becomes the jet
Casing	Holds everything together

When fired, the detonator ignites the rear of the explosive. The wave races forward, collapsing the copper liner inward. The collapsing metal squeezes itself into a jet that streams forward at extreme speed.

How the Jet Penetrates

The copper jet isn’t really “molten” — it’s solid copper flowing like a fluid because of the extreme pressure (~200 GPa). At the contact point with armor:

Pressure of jet > strength of armor
Both behave like liquids
The jet squirts through the armor as easily as water through butter

Penetration depth is roughly 6–8 times the diameter of the warhead. So a 100 mm HEAT warhead can penetrate ~700 mm of steel armor.

Famous HEAT Weapons

Weapon	Type	Penetration
RPG-7	Anti-tank rocket launcher	250–600 mm (different rounds)
AT4	Disposable launcher	420 mm
PzF 3	Panzerfaust 3	700 mm
TOW-2A	ATGM	700+ mm (tandem)
Javelin	ATGM (top-attack)	600–800 mm
Kornet	ATGM	1,200 mm (tandem)
Hellfire	Helicopter-launched	1,000 mm (tandem)
L-UMTAS / OMTAS	Türkiye	1,000 mm+
M830 HEAT-MP	120 mm tank round	~700 mm

The Tandem Warhead — Beating Reactive Armor

Modern tanks wear ERA (Explosive Reactive Armor) — small bricks of explosive that detonate outward when hit, disrupting incoming jets.

Tandem warheads have two charges:

1. A small precursor charge that sets off the ERA
2. The main charge that defeats the now-bare armor underneath

Famous tandem HEAT: Kornet, TOW-2A, RPG-29, Javelin.

HEAT Velocity Doesn’t Matter

A key advantage of HEAT: penetration is determined by the shaped charge, not by impact velocity. Whether the missile is moving fast or slow, the warhead works the same.

This is opposite to APFSDS (kinetic), where you need huge velocity.

That’s why HEAT is the favorite warhead for:

Slow ATGMs
Rifle grenades
Static mines (top-attack EFP)
Submunitions

HEAT Limits

Spaced armor (gap between two armor layers) disrupts the jet because it gets longer-but-thinner.
Slat armor / cage armor prematurely detonates the warhead at the wrong distance.
ERA disrupts the jet (defeated by tandem).
Active Protection like Trophy or Iron Fist shoots down the round before impact.

EFP — A Cousin of HEAT

An Explosively Formed Penetrator (EFP) is a shaped charge where the liner forms a single slug (not a jet) traveling at 2,000–3,000 m/s. EFPs are used in:

Top-attack anti-tank mines (e.g., FFV 028, German PARM)
IEDs in Iraq War — Iranian-made EFPs killed hundreds of US troops
Some loitering munition warheads

EFPs penetrate less than HEAT but work at much greater distance.

A Kid-Friendly Analogy

If you punch a wall with your fist, you hurt your hand and damage some paint. But if you push a needle into the same wall with the same force, the needle goes deep.

A normal explosion is the fist. HEAT is the needle — same energy, but focused into a tiny point that can pierce anything.