K21

Development of the K21 began in 1999 to replace the South Korean K200 series. Formerly designated as the K300 or XK21, the vehicle was designed by the Agency for Defense Development with Hanwha Defense as the primary manufacturer. Following the delivery of three prototypes in 2005, production began in 2009. A redesign of the amphibious systems was initiated after two vehicles sank during operations due to buoyancy and drainage malfunctions.

The chassis is constructed from aluminium alloy and fiberglass components. Armor protection consists of layered glass fiber reinforced ceramic composites, providing defense against 14.5mm projectiles and 20mm fragments. The frontal armor resists 30mm APDS rounds, while the roof is protected against 155mm artillery fragments. Internal safety features include a self-sealing fuel tank and an automatic fire suppression system. The K21 Product Improvement Program (PIP) variant incorporates explosive reactive armor and hard-kill active protection systems.

Firepower is centered on a 40mm autocannon capable of firing armor-piercing fin-stabilized discarding sabot (APFSDS) and multi-mode fused ammunition. The fire-control system allows for hunter-killer operations via independent stabilized sights for the commander and gunner, both equipped with third-generation thermal viewers and laser rangefinders. Secondary armament consists of a 7.62mm machine gun and provisions for anti-tank guided missile launchers.

The vehicle utilizes a turbocharged diesel engine and an in-arm suspension unit. For amphibious operations, a pontoon system provides buoyancy. The interior accommodates a three-man crew and nine passengers, with a battle management system providing situational data via internal displays and external camera feeds.

The Republic of Korea Army operates the K21 in large numbers. Australia selected a derivative variant, the AS21 Redback, which features a 30mm autocannon, anti-tank missiles, and an active protection system. A medium tank variant, the K21-105, has been developed using the same chassis equipped with a 105mm rifled gun. The platform has also undergone evaluation for defense requirements in Poland, Romania, and Latvia.