The Challenger 3 Might Soon Be NATO’s Best Tank (But 1 Problem Looms)

Challenger 3 Will Be the British Army’s Mainstay—But Will It Be Enough?: Additions and improvements to the Challenger line of British tanks are impressive, but low procurement numbers may ultimately hold the tank back.

Challenger 3: Great Tank, Low Numbers

The Challenger 3 main battle tank is a serious and significant step forward for the British Army and marked one of the most substantial armor modernization programs in recent history for the United Kingdom—the origins of the Challenger 3 program lie with the Challenger 2.

In light of that platform’s shortcomings, improvements aimed at extending service life and improving the main battle tank’s combat effectiveness have yielded not just an upgrade package but a thoroughly new design.

Centered around a new turret, a new main gun, and extensive technological improvements, the Challenger 3 offers improved protection, better battlefield performance, and simplified logistics compared to the Challenger 2 predecessor.

120 millimeters of NATO-Standard Ammunition

By far and away, one of the most significant changes implemented onto the Challenger 3 is the replacement of the Challenger 2’s rifled L30A1 120mm main gun with a smoothbore 120mm gun, more specifically, the Rheinmetall L55A1. This smoothbore design is a considerable departure from the British tank design philosophy. In a huge break from the rest of NATO, the British opted for a rifled main gun barrel rather than a smoothbore barrel. The Brit’s rifled barrel fires high-explosive squash head (HESH) rounds, particularly valued for their usefulness against armored vehicles and fortified positions.

By changing to a smoothbore gun, the Challenger 3 will no longer employ HESH rounds as a primary ammunition type, as smoothbore guns lack the rifling to impart a stabilizing spin on projectiles. This change, in essence, ends the British Army’s use of that specific type of tank ammunition, representing a major doctrinal shift.

A Redesigned Main Gun

However, the upswing is better flexibility, increased compatibility, and simplified logistics for the British Army and the rest of the NATO alliance: by adopting a smoothbore main gun, the Challenger 3 fires the full gamut of NATO-standard 120mm tank ammunition, which includes, armor-piercing fin-stabilized discarding sabot (APFSDS) rounds and programmable high-explosive ammunition, which are in service with the German Leopard 2 (in service widely across Europe, M1 Abrams in service with Poland and the United States, as well as with the French Leclerc and other platforms. The interoperability of NATO-standard 120mm ammunition also allows the British to dip into NATO ally ammunition stocks and, conversely, to keep NATO allies in the fight to a greater degree than was previously possible.

But besides the new main gun, the most significant change to the Challenger 3 over the Challenger 2 is its turret. The turret redesign allows the tank to accommodate the new smoothbore main gun. It also incorporates enhancements to the tank’s armor protection, upgrades to electronics, and an improved digital system that aids target acquisition, fire control, and situational awareness. The new tank’s turret is fully digitized, which allows faster and more reliable data sharing between crew members and across units on the battlefield.

The Hull

The Challenger 3’s hull is essentially based on the Challenger 2 design but with upgrades incorporated. Improvements to the tank’s armor package, mobility, and survivability are also expected to aid survivability in combat scenarios. However, its active protection system is one of the Challenger 3’s biggest improvements.

Arguably, one of the most notable features of the Challenger 3’s defenses is its active protection system. While previous British tanks, including the Challenger 2, relied on passive layers of armor for protection, including classified Chobham and Dorchester composite armor, which the Challenger 3 lacked, an active protection system detected and took down incoming projectiles. That added level of survivability is what the British Army hopes will keep the Challenger 3 upgrade relevant for many years to come, even in high-threat environments.

Show Me the Numbers

Though that outlook may be positive, it is not all rosy for Challenger 3. One aspect hampering the program? Sheer numbers. The Royal United Services Institute, one of the leading British defense think tanks, recently wrote about the Challenger 3 situation in a brief assessment of the British military. The picture it painted was far from rosy.

“Similarly, when RUSI analysts last looked at the Army, and the combat division the UK claims to have, it measured the number of main battle tanks and self-propelled artillery in the UK’s inventory and found the numbers wanting when set against a ‘credible’ armoured division of anywhere from 170 to over 300 tanks and around 110 to 220 artillery pieces. The numbers have not improved in the subsequent four years: under the Challenger 3 programme the UK will have a total of 148 main battle tanks (in 2030).”

“Meanwhile, the UK has essentially removed the AS90 artillery from service by donating 32 to Ukraine, replacing them with 14 Archer guns until such time as the ‘Mobile Fires Platform’ is procured (some time ‘this decade’). The Challenger 3 may be the ‘most lethal tank’ ever fielded by the British Army, but it is going to be available in such limited numbers that it will have to perform heroically in the face of a notional foe in the form of Russian ground forces, such as a Combined Arms Army.”

What Happens Now?

Although the Challenger 3 upgrade program does have its positive aspects, including increased lethality and better interoperability within the NATO alliance, the factor that may ultimately hobble the program is the low number of Challenge 3s that will eventually be built and put into service. Given the huge numbers of tanks in service with both Russia and Ukraine, it would be reasonable to assume that a tank fleet of just 150 or so tanks—even if doubled to 300 would not be near enough to maintain deterrence. So, despite the comprehensive suite of upgrades, it might be some time before the Challenger 3 fleet is a credible armored fighting force.

About the Author: Caleb Larson

Caleb Larson is an American multiformat journalist based in Berlin, Germany. His work covers the intersection of conflict and society, focusing on American foreign policy and European security. He has reported from Germany, Russia, and the United States. Most recently, he covered the war in Ukraine, reporting extensively on the war’s shifting battle lines from Donbas and writing on the war’s civilian and humanitarian toll. Previously, he worked as a Defense Reporter for POLITICO Europe. You can follow his latest work on X.

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