The Giant Cannon Is the Bigfoot of Modern Tank Design

Rumors abound about a bigger Russian gun—but where’s the proof?

For decades, Western analysts have predicted that Russia would introduce a giant new gun for its tanks—one that could blast right through the armor on U.S. and allied fighting vehicles.

To this day, the terrifying cannon has never appeared. But rumors of a giant gun—with a caliber between 130 millimeters and 152 millimeters—persist.

The weapon is the tank-design equivalent of Bigfoot.

The exact origins of the giant Russian tank gun are difficult to discern. American and Russian armorers—along with the Germans and others—have experimented with large-bore guns off and on since World War II.

However, plodding super-heavy tanks—and the monstrous main weapons they could potentially carry—rapidly fell out of favor as warfare became increasingly mobile in the 1960s and beyond. Instead, the Soviets focused on relatively small, low-profile vehicles for the rest of the Cold War.

Small turrets didn’t lend themselves to the huge ammunition the bigger cannons needed. Engineers might find room for 25 or 30 large rounds in the same cramped spaces that could fit 40 smaller shells.

Still, the USSR’s main battle tanks did sport progressively bigger main guns between 1945 and 1965. The vehicles’ barrel diameters jumped from 100 millimeters to 125 millimeters. By contrast, the 105-millimeter cannon was the standard for NATO tanks right into the 1980s.

Above—a 2A46M1 125-millimeter cannon. Photo via Wikipedia. At top—a Russian T-90A. Vitaly V. Kuzmin photo via Wikipedia

“The Warsaw Pact will outproduce NATO in large-gun, advanced-armor tanks more than 4:1,” warns a recently declassified Central Intelligence Agency article from 1980. Members of the NATO alliance finally closed this “gun gap” by the end of that decade, with 120-millimeter cannon designs of their own.

Amid this parity, American and European analysts worried that enemy cannons would just keep getting bigger. The Soviets could readily turn the “new long-barreled 152-millimeter field gun of the 2S5 self-propelled gun” into a deadly anti-tank weapon, explains a piece in a 1985 issue of Armor, the official publication of the U.S. Army’s tank branch.

In the end, the Soviets never fielded any massive guns on tanks or tank destroyers. Russia’s current T-80s and T-90s still use upgraded versions of the 125-millimeter 2A46 gun that first entered service more than 50 years ago.

Granted, separating fact from fiction could be extremely difficult during the Cold War. Gathering information on Soviet armament was like “reading tea leaves,” says Steven Zaloga, a senior analyst at the Teal Group and expert on armored vehicles.

As a result, the Pentagon continued to worry about gigantic tank guns even after the Berlin Wall fell and the Soviet Union collapsed. In the decade that followed, Armor continued to publish profiles that described future enemy vehicles with extra-large cannons.

When old Soviet archives and museums finally opened to the public, Western intelligence agencies and armor historians began to realize that many of the scariest Soviet tanks were one-offs or completely fictitious.

Only one Soviet Objekt 279 heavy tank—packing an awesome 130-millimeter weapon—ever existed. The similarly-armed IT-130 tank destroyer was likely a myth.

Look, bigger guns are more expensive simply because they require more raw materials and effort to build. “The Soviet Union and the Russians have always been very cost-conscious,” Zaloga notes.

Objekt 279 on display at the Kubinka Tank Museum. Photo via Wikipedia

Many of these experimental designs also suffered from political infighting between factories and also from constant changes in Kremlin leadership. Upheaval continued as the nation ditched communism for capitalism.

“It is very difficult when designing advanced weapons to get a lot of money one year and see it taken away the next,” Zaloga notes. “There have been a whole string of [Soviet and Russian] next-generation tanks that failed.”

The Russian army is hoping to get brand-new T-15 tanks some time in 2015 as part of the Armata program. And Zaloga expects the new armored beast to be similar the relatively roomy American M-1 or German Leopard 2—in other words, a clean break from Soviet-era tank design, which emphasized small, hard-to-spot vehicles.

A larger overall layout could theoretically open the door for one of the legendary massive cannons to finally make an appearance on an actual front-line tank. But sheer practicality is more likely to compelUralvagonzavod—Russia’s last tank factory—to use some sort of upgraded 125-millemeter weapon on the T-15.

And there are also firepower advantages to sticking with a more modest gun size. “The 120 caliber has continued to be a more powerful weapon,” Zaloga explains.

That’s due in part to intensive R&D on new cannon rounds. Having standardized their guns, the Russians—along with the Americans and the Germans—worked on improving their ammo. All three countries are working on even more lethal armor-piercing, fin-stabilized, discarding-sabot ammunition.

These APFSDS rounds launch massive darts of dense metal such as tungsten or depleted uranium. The penetrators rely more on speed and accuracy than sheer size.

A T-15 with an 125-millimeter cannon shooting faster-flying projectiles would probably be just as deadly as one with a much larger main gun. It doesn’t make sense to buy a gigantic new cannon if better ammo has as much destructive effect.

Still, the Western defense press and their sources insist on reporting “sightings” of tanks with huge main weapons—even outside of Russia. Reports in 2003 claimed the Chinese were working on one of their own.

Reports of a new Russian tank with a 152-millimeter gun surfaced again in 2008. And fearing the reports are true, the Pentagon is apparently still doing concept work on a new M-1 variant with a 140-millimeter gun the military hopes will match the terrifying new Russian weapon.

The Pentagon, NATO and others might not have to wait much longer to find out if there is any truth to their decades-old gun fears. Moscow hopes to parade its brand-new T-15 tank at next year’s May Day celebrations in Red Square.

The new tank probably won’t have a new gun. But maybe, finally, it will. “With the Russians, you can never say never,” Zaloga says