The Ukrainian army has armed its ex-Slovenian M-55S tanks with at least two kinds of American-made 105-millimeter shells for their classic, British-made L7 main guns.
One shell is for destroying bunkers. The other, for knocking out light armored vehicles.
The M-55Ss’ ammo loadout nods toward their role. The 36-ton, four-person M-55S—an Israeli upgrade of a Soviet-made T-55 tank that equipped a Slovenian army’s tank battalion in the early 2000s—is pretty lightly armored for a tank.
Its steel armor and layer of add-on reactive armor offer protection equivalent to maybe 300 millimeters of steel. That’s just half the protection a Russian T-72B3 or Ukrainian T-64BV enjoys.
The Ukrainian army’s 67th Mechanized Brigade, the only user of the 27 surviving ex-Slovenian tanks—the Russians knocked out one of the tanks in July—would be crazy to deploy the aged tanks as tanks, in direct mechanized assaults on stiff Russian defenses. Even Ukraine’s best-protected tanks, its ex-Swedish Strv 122s, get into trouble in direct attacks.
Wisely, the 67th Brigade apparently is using the M-55Ss as mobile guns as it fights a mostly defensive action against Russian attacks around Kreminna in northeast Ukraine. The tanks in essence are infantry-support weapons that follow behind the infantry fighting vehicles instead of leading them.
The M-55Ss’ ammo loadout, depicted in a photo that circulated online this summer, is what you’d expect for a mobile gun. It includes the M393A3 and the M456A2. The former is a squash-head round that pancakes on the outside of a fortification and fragments the inside; the latter is a high-explosive round for blasting through thin armor.
Imagine 67th Brigade infantry advancing in their BTR wheeled fighting vehicles and Tigr armored trucks. They run into a Russian strongpoint in a building, perhaps reinforced by BMP fighting vehicles.
The strongpoint is too tough for the lightly-armed BTRs and trucks; it’s not too tough for an M-55S firing squash-head and high-explosive rounds.
The other clue that the 67th Brigade is deploying its M-55Ss as mobile guns, and not as tanks, is that it’s lost just the one copy. The ex-Slovenian ex-T-55s despite their thin armor might have one of the lowest loss rates of any Ukrainian tank type. The Ukrainians clearly aren’t assigning them to the riskiest missions. For example, breaching Russian minefields and trenches.
That the M-55Ss are firing M393A3s and M456A2s might mean they’re also firing the other American 105-millimeter tank rounds that the administration of U.S. president Joe Biden pledged to the Ukrainian war effort back in April. They include M1040 canister rounds, which scatter 2,000 tungsten balls like giant shotgun shells and can decimate unprotected infantry.
These ammo types are about to become a lot more important in the coming months as Ukraine receives the initial batches of nearly 200 German-made Leopard 1A5 tanks, which have the same L7 gun that the M-55Ss have—and might end up in the same roles as the ex-Slovenian tanks.