Super-Upgraded M-55S Tanks Have Arrived In Ukraine

The first video has appeared online depicting the Ukrainian army’s ex-Slovenian M-55S tanks.

The video depicts what appears to be a four-person M-55S crew training on its new-old vehicle. The thick mud—a sticky hallmark of Ukraine’s wet early winter—might confirm the video is recent.

The M-55S despite its age could represent a glimpse at the Ukrainian army’s tank future. It’s all about the gun.

The M-55S is a deeply modernized Soviet T-55, a tank type that first entered service in the late 1950s. In the 1990s, the Slovenian army paid Israeli firm Elbit and STO RAVNE in Slovenia to modify 30 of its 36-ton T-55s.

The companies delivered the last example in 1999. The Slovenian army in the early 2000s replaced the M-55Ss with newer M-84s—and put the M-55Ss in storage.

Slovenian prime minister Robert Golob in a telephone conversation with German chancellor Olaf Scholz in September hammered out a deal whereby Germany would give Slovenia 40 military trucks—and Slovenia in turn would supply 28 M-55Ss to Ukraine. That’s enough tanks for a single battalion.

Among other enhancements—including reactive armor, an uprated engine and a new fire-control system—the M-55S has a stabilized, British-made L7 105-millimeter main gun in place of the original Soviet 100-millimeter gun.

The gun is what makes the M-55S valuable to Ukraine. The British gun is compatible with a wide range of modern ammunition, including armor-piercing sabot rounds that can penetrate the armor of a modern T-72.

More importantly, several Western companies produce 105-millimeter shells, meaning Ukraine shouldn’t struggle to maintain a steady supply of ammunition for its single M-55S battalion.

The same can’t be said of the scores of old T-62s the Ukrainians recently have captured from the Russian army. The first Ukrainian unit re-equipped with T-62s no later than mid-November.

The Ukrainians have enough ex-Russian T-62s for perhaps two battalions. The problem, for these units, is that the T-62 packs a 115-millimeter main gun that’s unique in Russian and Ukrainian service.

The Russian army might be sitting on big stocks of 115-millimeter shells. The Ukrainian army, which last operated T-62s in the late 1990s, almost certainly isn’t. Ammo supply could be the main constraint on Ukrainian T-62 operations. It shouldn’t limit M-55S ops, however.

The M-55S despite the age of its underlying design also is a transitional type for the Ukrainian army. The M-55S’s hull is Soviet. Its weaponry is Western.

Today the Ukrainian army and marine corps operate more than a thousand tanks. All but the M-55Ss are purely ex-Soviet models.

Some day, perhaps after the current war has ended, Ukraine might finally acquire Western tanks: German Leopards or American M-1s, perhaps. It’s worth noting that early Leopards and early M-1s both have the same L7 gun the M-55S has.

In that sense, the M-55S might be preparing the Ukrainian army for its possible future as an operator of NATO-style tanks.