The Latest Russian Drones Fire Lethal Slugs Of Molten Metal

Russia’s newest Lancet explosive drones apparently fire slugs of molten metal that can shoot right past the add-on armor Ukrainian troops count on to protect their vehicles from drone attacks.

If there’s any good news for the Ukrainians in the proliferation of drone-fired explosively formed penetrators, or EFPs, it’s that the best-protected vehicles should be able to deflect the strikes.

Keen-eyed observers months ago spotted—in photos and videos from the front—what they believed were EFP-armed Russian drones. Now wider acceptance is sinking in.

“A video of the latest iteration of the Lancet loitering munition equipped with such a warhead striking a Bradley [fighting vehicle] was recorded on the Donetsk axis,” the independent Conflict Intelligence Team noted this week.

A sensor aboard an EFP-armed drone—a laser ranger, in the case of the Lancet—calculates the distance to the target as the drone barrels in. At the best distance, 12 or 15 feet, the sensor triggers an explosive charge that sits behind a curved metal plate.

Propelled and heated by the charge, the plate lances outward—and takes the shape of a long slug. This slug pierces the target.

An EFP isn’t as powerful as is, say, a high-explosive anti-tank—HEAT—warhead that directly strikes its target. The main advantage of an EFP is that it ignores certain kinds of armor. For instance, bolt-on slats and cage armor that can detonate high-explosive rounds at a safe distance, and which also tend to snag explosive drones before they explode.

Both the Russian and Ukrainian militaries routinely add slat or cage armor to many of their combat vehicles. The armor is an expedient and doesn’t always work. But it will work even less often for the Ukrainians now that the Russians apparently are equipping their Lancets with EFPs.

There are countermeasures. To defeat EFPs in Iraq, the U.S. Army added composite armor to many of its vehicles. The main problem with this additional protection was the weight. One example: EFP-proof armor added a ton of extra mass to a three-ton Humvee, severely limiting the vehicle’s mobility.

Explosive reactive armor might work. “Since the 1970s, this has been used to defeat HEAT and EFP rounds by exploding small charges outward from the armor, interrupting the penetrating blast,” Capt. Vincent Delany, a U.S. Army infantry officer, noted in an essay for West Point’s Modern War Institute.

Explosive armor also adds weight. More troublingly, explosive armor explodes. You can’t hang ERA on a thin-skinned vehicle without the armor’s own blasts damaging the vehicle. “Behind all ERA must be passive armor such as [rolled steel],” Sam Cranny-Evans and Sidharth Kaushal explained in a study for the Royal United Services Institute in London.

All that is to say, the Ukrainians have some troubleshooting to do. There are ways of grounding and intercepting drones—jammers and air-defense guns, for example—and there are ways of protecting heavier vehicles against EFPs.

But these measures could leave many vehicles exposed. Especially lighter ones that can’t handle ERA. The usual anti-drone expedients—slats and cages—no longer are enough.