We Don’t Know What Kind Of Ammo Ukraine Is Getting for Its Leopard 1 And M

M-55S tanks in service with the Ukrainian army's 47th Assault Brigade.

Arguably the best tanks in the world—American M-1s and German Leopard 2s, to name two—have 120-millimeter cannons that, with the right sabot-discarding ammunition, can pierce the equivalent of a thousand millimeters of steel from thousands of yards away. That's enough to destroy pretty much any armored vehicle in existence.

But Ukraine is getting just 71 Leopard 2s from its European allies and 31 M-1s from the United States. A hundred tanks for an army that needs more than a thousand tanks to equip all of its armor battalions.

Ex-Soviet tank types—produced locally, recovered from long-term local storage or captured from the Russians—are, and should remain, the Ukrainian army's most numerous tanks.

But Kyiv also is getting at least 100 1980s-vintage Leopard 1s from a German-Dutch-Danish consortium, and already has received 28 M-55Ss from Slovenia. The Leopard 1 and M-55S come armed with a smaller and less powerful 105-millimeter gun: the classic L7 from the United Kingdom's Royal Ordnance Factory.

There's no way an L7 can penetrate a thousand millimeters of steel and match the performance of a newer 120-millimeter gun. But with the right shell, it might get close.

The thing is, we don't know what kinds of 105-millimeter tank ammunition Ukraine plans to feed its Leopard 1s and M-55Ss. It makes all the difference.

The M-55S is a late-1950s-vintage T-55 that Israeli firm Elbit deeply upgraded for the Slovenian army back in the 1990s. Working with a constellation of Slovenian firms, the Israelis gave the tank a new gun—the L7—plus reasonably modern day-night optics and modern fire-controls. Add-on reactive armor and an uprated engine rounded out the upgrade.

The German government last fall essentially financed the transfer to Ukraine of 28 M55Ss, by giving the Slovenian government dozens of military trucks in exchange. There's a good chance that the Israeli government quietly signed off on the M-55S deal. And that's why it's not inconceivable that the transfer also included the same DM63 ammunition that armed the tanks when they were in Slovenian army service.

The DM63 is a German copy of Elbit's M426. The DM63 and M426 weigh 40 pounds. They’re sabot-discarding rounds—that is, shells containing a tungsten dart in a kind of shoe. The powder explodes, the shell blasts from the gun barrel, the sabot flies off and the dart lances toward its target like a hypersonic needle.

How much armor a DM63/M426 can penetrate depends on the range and angle to the target. The Taiwanese army, which fires DM63s from the 105-millimeter guns on its CM-11 tanks, pegs the maximum penetration at 600 millimeters, presumably at typical combat ranges between 1,000 and 2,000 yards.

That's probably enough to pierce the frontal armor on a mid-generation Russian T-72 tank. Against the latest Russian T-72B3, the DM63/M426 might inflict significant damage without actually destroying the tank.

Elbit however claims the DM63/M426 "is capable of defeating modern [main battle tanks], with high hit probability and penetration capabilities at all combat ranges." Then again, Elbit is trying to sell ammo.

There are alternatives to the DM63/M426. The United States arms its mobile-gun vehicles with M900 sabot rounds that also can pierce around 600 millimeters of armor. But the M900's penetrator is made of depleted uranium, which the U.S. government as a matter of policy doesn't export—not even to its closest allies.

The U.S. government this month pledged to the Ukrainian government an unspecified quantity of 105-millimeter tank ammo. Since the shells probably aren't M900s, it's possible they’re the next best thing: tungsten sabot rounds that American firm General Dynamics manufactures for export.

These C76A1 rounds penetrate just 400 millimeters of armor, as do similar M1060A2s from French company Nexter.

The difference between the best DM63/M426 shell and the less-capable alternatives is hundreds of millimeters of armor-penetration. In a pitched fight between a Ukrainian Leopard 1 or M-55S and a Russian tank, those hundreds of millimeters could be the distance between life and death for one crew or the other.

So it matters, a lot, what kind of ammo Ukraine's allies are providing along with those L7-armed tanks. Of course, Russian intelligence surely is as keen as we are to know what Russian tanks are up against in Ukraine. So don't expect the Ukrainians to volunteer a lot of information about their tank shells.