Here's What You Need to Know: Russia may finally have a 125-millimeter sabot round that can threaten Western main battle tanks at range.

The Soviet Union’s huge tank fleet was a cornerstone of its power during the Cold War.  However, events in the 1991 Gulf War called its superiority into question. On February 26, 1991, a cavalry troop of nine M1 Abrams tanks and twelve Bradley fighting vehicles bumped into an armored brigade of Iraqi T-72 tanks of the elite Tawakalna Republican Guard division. Within twenty-three minutes of frenzied firing, the troop destroyed thirty-seven of the Soviet-designed T-72s without losing a vehicle in return.

Such outcomes were not solely a result of superior U.S. training. Iraqi tankers did sometimes land multiple hits on M1 tanks, but their shells failed to penetrate the Abram’s frontal armor. Not one M1 was destroyed by hostile fire in the war.

Russian tank enthusiasts are quick to point out that the Soviet Union did not export to Iraq it’s more advanced 125-millimeter armor-piercing sabot shells, some of which used dense tungsten or depleted-uranium for increased penetrating power. After the USSR’s dissolution, Russian engineer continued developing improved ammunition. However, the effective thickness of frontal armor on Western tanks also increased by roughly 50 percent.

Todays, T-72s remain Russia’s primary main battle tank, supplemented by turbine-engine T-80s and four hundred more advanced T-90s. All carry variants of the 125-millimeter 2A46 smoothbore cannon, which loads its ammunition using a rotating ‘carousel’ mechanism instead of human loader. You can see the carousel in operation in this video.

Tanks employ a variety of different ammunition, including fragmenting high-explosive (HE) shells for combatting personnel and light vehicles, and high-explosive-anti-tank (HEAT) shells employing shaped charges that blast a jet of molten metal when they strike their target.  Because HEAT shells do operate based on kinetic energy, they do not lose power over distance. Russian tanks can also fire guided missiles through their gun tubes which use use HEAT warheads. Though slower than a shell, missiles are more accurate against very distant targets.

However, modern main battle tanks employ arrays of composite and/or explosive reactive armor, sometimes combined with active protection systems, which are particularly effective at defeating HEAT charges. Thus, the tank-busting munition of choice remains the kinetic-energy Armor-Piercing Find-Discarding Sabot (APFDS).

An APFDS round consists of a dart-like penetrator rod of ultra-dense metal contained within an finned aluminum “sabot,” which blossoms away like the petal of a flower upon exiting the gun tube, as you can see in this video. Kinetic penetrators do lose energy over distance, but are very difficult to defeat by means other than bulky armor.

Penetration can be augmented by increasing shell velocity (typically by lengthening the gun barrel), or increasing mass by enlarging shell diameter (difficult, as it considerably increases weight), the length of its penetrating rod, or the density of its metal.

Today, the Abrams, Leopard 2 and Challenger 2 are believed to possess frontal armor roughly equivalent to eight hundred millimeters of Rolled Homogenous Armor. Russia’s best armor-piercing shells compatible with the 2A46M gun is the 3BM59 Svinets-1 and 3BM60 Svinets-2, made of tungsten and depleted uranium respectively. These are estimated to penetrate 650 to 750 millimeters of 60-degree sloped armor at a medium combat distance of 2 kilometers (1.24 miles).

This still apparently leaves the Russian shells at a deficit versus Western armor, though not a hopeless one: they could still penetrate at shorter distances, or by striking the universally much weaker side or rear armor of any main battle tank. Purists will maintain the better (or luckier) tank crew can still prevail, but the challenge remains steep for Russian tankers, especially given the superior sights and fire control systems on Western tanks.

Making Sure the Ruby Sabot Fits

The Svinets was declared ready for production around 2002–2005, but evidence of mass production only emerged in 2016, which gives an idea of the arthritic financing of Russian defense programs. One problem was that the Svinets had penetrator rods 740 millimeters long, whereas the autoloaders on T-72s and T-80s could accommodate a maximum ammunition size of 640 millimeters. Thus enlarged 2A46M-5 and M-4 autoloaders had to be installed on upgraded tanks.

Russian engineers meanwhile were developing a huge new 2A83 152-millimeter gun intended to equip their next-generation T-14 Armata tank then under development, as well as an improved 125-millimeter gun called the 2A82 intended to upgrade older T-72 and T-90 tanks.

In 2003, three 2A82 prototype guns were produced and test-fired over 1,200 times. The weapon generated 20 percent more pressure on shells exiting the tube than a 120-millimeter gun on German Leopard 2 tanks, resulting in higher muzzle velocity, penetration and accuracy.

The 2A82 can employ new 3BM69 Vacuum-1 and 3BM-70 Vacuum-2 sabot shells (uranium and tungsten-based) with extra-long 900-millimeter penetrator rod. These could reportedly traverse 2 kilometers in a second, striking with fifteen megajoules of energy to penetrate 900–1000 millimeters of armor at that distance. If true, this finally gave Russia a tank shell that could reliably penetrate a Western main battle tank at medium range.

By 2010, Russian engineers had concluded the 2A83 gun was impractically large and decided to equip the Armata with the 2A82 instead, though this change was not made public until years later. Moscow also boasted it would purchase 2,100 Armata by 2020. However, it eventually transpired Russia would only procure a little over 100 T-14s by that date.

According to Russian defense blogger Alexey Khlopotov, orders for 2A82 guns mirrored the small number of operational Armatas. Initially a total of thirteen production-model 2A82-M1s were procured to outfit pre-productions  T-14s. A further 24 were purchased in December 2017, allowing outfitting of a full battalion of 36 T-14s.

Slow Armata procurement implied that Russia’s 2,000 T-72s and roughly 800 T-80s and T-90s in active-duty units had long services lives ahead of them. Thus in 2017, Russian defense media reported Moscow planned to upgrade its T-90s tank with Armata technology, including the 2A82 gun.

In 2019, the upgraded T-90M began undergoing trials, reportedly boasting hunter-killer-capable Kalina fire control system that can automatically tracks targets, upgraded explosive reactor armor and possibly a new active protection systems.  But the Vacuum-capable 2A82 gun remained missing in action.

In another article, Khloptov sheds light on the root problem: Russian engineers simply couldn’t find an economical way to stuff an autoloader capable of carrying the nearly meter-long Vacuum rounds into the cramped turrets of the older Russian tanks.

Apparently, in the early 2000s the Omsk factory studied building a dual-feed autoloader, in which the longer sabot shells were stowed in a separate horizontally-inclined mechanism.  However, the new system would have required lengthening the tank chassis and adding a seventh roadwheel. As this defeated the goal of saving costs by upgrading older vehicles, the revised turret was abandoned in 2009.

A more successful approach was to carve 80-millimeter-deep chunks out of each side of a T-72 or T-90 tank turret to accommodate a wider-diameter autoloader. The cuts were patched with extra armor on the exterior, and a modified firing mechanism proved capable of loading the shells.

This modification may have been used on unique T-72 and T-90s testbed tanks outfitted with a 2A82 gun.  However, Khlopotov comments:

“2A82 will not even be on the forthcoming Russian Army T-90M MBT. Simply because it turned Russia’s industrial sector cannot produce it.”  Khlopotov blames mismanagement of the Russian metallurgical industry.

Thus, while Russia may finally have a 125-millimeter sabot round that can threaten Western main battle tanks at range, only its handful of new T-14s tank are capable of actually using it. Optimistic claims that the 2A82 gun could be retrofitted to numerous older T-90s and T-72s so far appear not to have materialized.

Sébastien Roblin holds a master’s degree in conflict resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing, and refugee resettlement in France and the United States.

This article first appeared in 2019.

Image: Reuters