Ukraine’s M-55S Tanks Weren’t Supposed To See Heavy Fighting

As the Ukrainian military was preparing for its long-anticipated counteroffensive, which kicked off across southern and eastern Ukraine in early June, it doled out to newly-formed brigades much of the heavy equipment Kyiv’s foreign allies recently had donated.

The army’s new 47th Mechanized Brigade got a combat vehicle windfall, in the form of 90 American-made M-2 infantry fighting vehicles, all six Finnish Leopard 2R mineclearers and all 28 M-55S tanks Slovenia had pledged to the war effort.

The 47th Brigade this spring busied itself training with its new vehicles. But then something strange happened. When, in the weeks before the counteroffensive began, the 47th finally deployed to southern Ukraine’s Zaporizhzhia Oblast, it deployed without its M-55Ss.

By now we can say with confidence where the ex-Slovenian tanks wound up. Just west of Russian-occupied Kreminna in northeastern Ukraine, with another new army brigade: the 67th Mechanized. Equipping a small-ish battalion, the M-55Ss fight alongside T-72s equipping the 67th Mechanized’s full-size tank battalion.

The evidence slowly piled up. On July 12, Alina Mykhailova, a medical officer with the 67th Brigade, photographed an M-55S inside a treeline west of Kreminna. A few days later, one of the 36-ton, four-person M-55S ate a Russian artillery shell that wrecked the tank’s Israeli-made optics—a strike observers geolocated to the area outside Kreminna.

And on or right before July 22, a second M-55S took a direct hit—again outside Kreminna—and exploded.

Why the 47th Brigade would chop its only tanks to the 67th Brigade is unclear. It’s possible the Ukrainian general staff worried that the M-55S—a heavily-upgraded, ex-Soviet T-55 with a British-made 105-millimter gun—is too vulnerable for the kind of fighting the 47th has endured along the Tokmak axis in southern Ukraine.

Yes, the tank has layers of explosive reactive armor. But the steel underneath the ERA is just a couple hundred millimeters thick at its thickest. That’s modest protection by today’s standards.

In one sense, Ukrainian commanders were right. In the south, the 47th Mechanized Brigade has teamed up with the 33rd Mechanized Brigade, which operates the all 21 Leopard 2A6 tanks Portugal and Germany donated to Ukraine. The Leopard 2A6 in places has protection equal to a whopping 1,400 millimeters of steel. Even so, the battalion operating the 69-ton tanks has lost at least two of them. Another nine have suffered damage.

But if commanders were hoping to keep the M-55Ss away from the most intensive fighting, they miscalculated—badly. Because it’s west of Kreminna that the Kremlin chose to concentrate its best available forces for a countercounteroffensive the Russians clearly hoped would spoil Ukrainian operations farther south.

Russian brigades have advanced a few miles west of Kreminna. But Ukrainian forces—not just the 67th with its M-55Ss, but also the 21st Mechanized Brigade with its arsenal of cutting-edge Swedish-made vehicles—have prevented major advances. Spoiling the spoiler.

The Ukrainians may have tried to save the M-55S battalion from a direct clash with some of the best Russian forces. But the attempt to spare the unit ironically placed it directly in the path of … some of the best Russian forces.