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K21 Infantry Fighting Vehicle

South Korea


K21 Medium Tank CT-CV 105HP Image #2
Unveiled / Entered Service
K21 Infantry Fighting Vehicle
In Service
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The K21 is an indigenously developed South Korean Infantry Fighting Vehicle in service with both the Republic Of Korea Army and the Australian Army. It is heavily armed with sophisticated sighting technology, well armoured and has all round good mobility.


The ROKA had been operating a series of APC’s based on the American AIFV since the mid 1980’s designated the K200. Like all modern armies, the ROKA made the decision to move its armoured infantry from APC’s to a more capable Infantry Fighting Vehicles.

South Korea had relied on vehicles supplied by America, post the Korean War and moved to manufacturing fighting vehicles based on designs jointly developed with American assistance through the 1980’s and 1990’s, before under taking full development in the 2000’s.

The K21 is not only South Korea’s first true IFV, but is another indigenously developed fighting vehicle that has attracted foreign export clients.

With a budget of roughly $97,000,000, development of the K21 started in 1999 and was led by the Agency for Defense Development (ADD) and Doosan Infracore, as well as eleven other South Korean defense sub-contractors.

The first three prototypes was passed to the ROKA for extensive trials work in 2005. The eight year development program was complete in 2007, with production starting in 2009.


Most modern Infantry Fighting Vehicles protection is rated to protect against 30mm, medium calibre chain gun AP rounds.

The K21 is equipped with the K40 40mm chain gun, which is capable of firing programmable ammunition as well as HE and AP rounds designed to defeat with ease, the frontal armour of other Infantry Fighting Vehicles. It can also be used to engage low-flying helicopters.

The K40 is mounted in the two man turret (commander left, gunner right) and is fed by an interchangeable x25 round magazine. It has three feeds in the magazine for PFHE, APFSDS and MMFA rounds.

Its anti-tank capability comes in the form of a dual launcher located on the left side of the turret, which fires the 3rd generation, fire and forget, Raybolt. This ATGM features a tandem charged warhead designed to defeat both a tanks Explosive Reactive Armour and base ceramic armour.

The K21 features the latest detection and fire control systems, with similar capabilities as the K2 Black Panther tank and features a Commanders Independent Sight, allowing the Commander to search for new targets independently of the gunner whilst he is engaging a target.


Very little is known about the vehicles ballistic protection. Its understood that the vehicle is manufactured in a hardened fiberglass and aluminum lending the vehicle high levels of protection. It is not uncommon for a vehicles armour to be rated against its main gun. In addition, the external surfaces are covered in unspecified modular armoured plates as standard.

Other safety features include a Nuclear Biological Chemical air filtration system, fire detection and suppression system and self sealing fuel tanks.

The vehicles layout also gives additional protection. The driver is off-set to the front left of the hull and the engine compartment to his right, which acts as both spaced armour and a physical block (the engine) to penetrate. A bank of x5 smoke grenade launchers is mounted on both sides of the turret and used to mask the vehicles signature to the enemy.


 K21 Infantry Fighting Vehicle Flotation Device
K21 Infantry Fighting Vehicle Flotation Device

The K21 has a very unique system used to pass rivers and water ways quickly as well as stabilise it whilst firing on the water, a set of self inflating buoyancy bags on both sides of the hull.

This benefits the ROKA by eliminating the need to create vulnerable crossing points using temporary bridges and allows the K21 to cross any water obstacle along a border of their choosing.

It’s mobility components are fully indigenous, with a 750hp Doosan D2840LXE turbo-inter-cooled diesel engine and automatic transmission as well as hydrogas suspension, which allows the K21 to travel faster off-road and provides more stability for firing on the move.

Variants and Marks

Since 2013, Doosan and CMI Defence (known as John Cockerill Defense since 2019) have exhibited the K21 with different models of their modular turret range at international defense exhibitions, with signage describing the vehicle as a medium tank.

K21 Medium Tank CT-CV 105HP

K21 Medium Tank CT-CV 105HP
K21 Medium Tank CT-CV 105HP

The elder of both turret systems, a modular design that features a 105mm rifled main gun fed with an auto-loader in the turret bustle magazine, which reduces the crew to only 2, Gunner and Commander.

K21 Medium Tank XC-8 105HP

Adex 2017 - K21 Medium Tank XC-8 105HP
Adex 2017 – K21 Medium Tank XC-8 105HP

The XC-8 turret features a 105mm rifled main gun fed with an auto-loader in the turret bustle magazine, which reduces the crew to only 2, Gunner and Commander. Both crews sights have a day and thermal channel, allowing the vehicle to operate in all-weather conditions 24hrs a day. It is fitted with the latest computerised Fire Control System with electrically controlled stabilization of the main gun providing high levels of accuracy whether the vehicle is static or moving.

K21 Medium Tank XC-8 120HP

K21 Medium Tank XC-8 120HP
K21 Medium Tank XC-8 120HP

The XC-8 is a modular turret. The 120HP referrers to the main guns calibre, the John Cockerill Defense 120mm Smoothbore (originally developed/manufactured by Ruag) compact tank gun, which is capable of firing all NATO L44 120mm smoothbore rounds.

Both XC-8 turrets have been seen on the K21 Medium Tank. Over the years the sights have changed and a commanders independent sight with the same shaped housing as the one used on the K21 IFV and K2 Tank has been added to the turret.

The XC-8 can be identified from the CT-CV by its smoke grenade launchers being embedded inside the turret on both sides.

Its worth noting that John Cockerill Defense no longer markets the XC-8 or CT-CV turrets.

AS21 Redback IFV

AS21 Redback
AS21 Redback

The latest version of the K21 developed for the Australian Army. It features the Israeli Elbit Systems MT30 Mk 2 Remote Weapon Station. READ MORE


South Korea

A total of 466 vehicles have delivered in three production batches. A forth batch of 120 vehicles was ordered with deliveries running from 2024 to 2028.


Winner of the Australian Army’s Land 400 Phase 3 IFV project, 129 AS21 Redback vehicles are on order and will be built in Australia with deliveries starting in 2027 and will replace the ageing M113AS4.


Main Gun
K40, 40mm medium calibre chain gun
ATGM Capability
Dual Raybolt ATGM launcher
Secondary Weapons
Coaxial 7.62mm Machine Gun
Ammunition Storage
750hp Doosan D2840LXE turbo-inter-cooled diesel
Top Road Speed
Road Range
Fuel Capacity
Vertical Obstacle
Water Capability
Trench Crossing
Side Slope
Length Gun Forward
Length Hull
Ground Clearance
25+ Tonnes
NBC Protected
Standard Armor(s) Type
Steel, Laminated
Optional Add-on Armor(s) Type
Active Protection Systems
Commander, Gunner, Driver