CN08 120 mm gun

The CN08 (Cannon 08) is a 120 mm 55-caliber smoothbore tank gun produced by Hyundai WIA. It is incorrectly known as the licensed production of the Rheinmetall Rh-120 L/55, but it was indigenously developed by the Agency for Defense Development and WIA (now Hyundai WIA) from 2003 to 2008 for the XK2 development project started in 1995. The development was completed after the field test ended in September 2008.

Design


The CN08 is the main armament of the K2 Black Panther, and the gun barrel is applied with internal chrome plating technology for the large-caliber gun. The gun barrel can endure a high explosive force as a result of the increased stiffness and wear resistance provided by this internal chromium surface. The main components, including the breech ring, breech block and thermal sleeve, are simplified and designed lightly, the gun barrel weighs 1324 kg and the gun mount weighs 3100 kg.

The gun mount consists of an eccentric hydro-pneumatic recoil system with oil reservoir for the gun barrel and is complemented by a bustle type autoloader powered by a main gun controller combined with a breech opening motor that automatically opens and closes the gun tube, it can fire up to 10 rounds a minute.

The maximum permissible pressure of the gun barrel is 744 MPa (108,000 psi), and when the tank gun fires an improved K279 APFSDS, the maximum proof pressure is 690 MPa, and the muzzle velocity is 1800 m/s. It depends on the type of ammunition, but the effective firing range of the tank gun is 8000 m.

Dynamic muzzle reference system
The main armament has a dynamic muzzle reference system (DMRS) consisting of a laser reflector, a laser emitter and a vertical sensor unit (VSU). A laser reflector assembly attached to the top of the thermal sleeve is provided to be adapted to a dynamic muzzle reference system to electro-optically measure the accurate position of the muzzle. The mechanical gyroscope type vertical sensor unit, which calculates the lead angle and superelevation in real time to correct the misalignment of the aim, allows the tank to more accurately hit its intended target even when it is maneuvering on irregular terrain.

Ammunition
CN08's 120 mm round is produced in Poongsan Corporation, a South Korean ammunition manufacturer, and can fire 120×570 mm NATO tank ammunition.

Turkey
On July 29 2008, Hyundai Rotem and Otokar signed a contract for technology transfer and design assistance for the Altay Tank Development Project. This contract includes technology transfer and design assistance for systems, armor package, and 120 mm guns required for Altay tank development.

Poland
On July 27, 2022, Polish Armaments Group (PGZ) and Hyundai Rotem signed a framework agreement to supply 180 K2s and 820 K2PLs. The agreement will include rapid arms supply and extensive technology transfer from South Korea, and 180 K2s will be produced in South Korea and delivered to Poland from 2022, and 820 K2PLs will be produced in Poland under license from 2026.

Variants

 * MKE 120 mm gun: Turkish 120 mm 55 caliber smoothbore gun modified based on CN08 for the Altay tank. The design of the tank gun is the same as CN08, but there are two differences: unlike CN08, thermal sleeve is equipped with Static Muzzle Reference System (SMRS), and Altay's turret does not have breech opening motor and automatic feeding magazine system for autoloader mechanism, so ammunition can only be loaded manually by tank crew and can fire up to 6 rounds a minute.

Current operators

 * 🇵🇱 – Polish Land Forces
 * 🇰🇷 – Republic of Korea Army

Weapons of comparable role, performance and era

 * L11A5 120 mm rifled gun: British rifled equivalent, developed by Royal Armament Research and Development Establishment (RARDE) in 1957.
 * 2A46 125 mm gun: Russian 125-mm equivalent, developed by Spetstekhnika Design Bureau in 1960s.
 * Rheinmetall 120 mm gun: German equivalent, developed by Rheinmetall in 1974.
 * CN120-25 120 mm gun: French equivalent, developed by Établissement d'Études et de Fabrication d'Armements de Bourges (EFAB) in 1979.
 * EXP-28M1 120 mm rifled gun: Experimental British weapon of the late 1970s/early 1980s. Was to have equipped the MBT-80.
 * CN120-26 120 mm gun: French equivalent, developed by EFAB in 1980s.
 * IMI 120 mm gun: Israeli equivalent, developed by Israeli Military Industries in 1988.
 * OTO Breda 120 mm gun: Italian equivalent, developed by OTO Melara in 1988.
 * L30A1 120 mm rifled gun: British rifled equivalent, developed by ROF Nottingham in 1989.
 * JSW 120 mm gun: Japanese equivalent, developed by Japan Steel Works in 2008.
 * 2A82-1M 125 mm gun: New Russian 125-mm equivalent, developed by Uralvagonzavod in 2014.