# 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 1,324 kilograms (2,919 lb) and the gun mount weighs 3,100 kilograms (6,800 lb).
The gun mount is composed 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 switched reluctance motor (SRM) combined with a breech controller that automatically opens and closes the gun tube, and 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 (100,076 psi), and the muzzle velocity is 1,800 m/s (5,900 ft/s). It depends on the type of ammunition, but the effective firing range of the tank gun is 8,000 meters (8,700 yd).

### 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.
APFSDS Rounds :
| Ammunition | Compatible tank gun | Type | Penetrator | Chamber pressure | Muzzle velocity | Ammunition weight | Ammunition length | Sub-projectile weight | Sub-projectile length | Penetrator weight with fin | Penetrator length with fin | Propellant type & weight | RHA penetration | Notes |
| K276 | CN03, CN08, M256 | APFSDS-T | Tungsten composite | 586 MPa | 1700 m/s (L/44) | 19.7 kg | 973 mm | 7.35 kg | 703.6 mm | | 600 mm | K683 (Triple-base) | >600 mm (LoS at 60° obliquity) at 2000 m | Penetrators are manufactured by Cyclic Heat-Treatment and a Double-Cycle Sintering process. |
| K279 (XK279) | CN08 | APFSDS-T | Tungsten composite | | 1760 m/s (L/55) | 21.3 kg | 998 mm | 8.27 kg | 761.6 mm | 5 kg | | 8.6 kg of L15190 (SCDB) | >700 mm (LoS at 60° obliquity) at 2000 m | The penetrator is made of W-Ni-Fe-Mo Alloy. |
| K279 Improved | CN08 | APFSDS-T | Tungsten composite | 690 MPa | 1800 m/s (L/55) | 21.3 kg | 998 mm | 8.27 kg | 761.6 mm | 5 kg | | 8.6 kg of 19-hole cylinder-type (SCDB) | | New DNDA-57 energetic plasticizer for stronger SCDB propellant. |
HEAT Rounds :
| Ammunition | Compatible tank gun | Type | Filler | Chamber pressure | Muzzle velocity | Ammunition weight | Ammunition length | Sub-projectile weight | Sub-projectile length | Filler weight | Propellant type & weight | RHA penetration | Notes |
| K277 | CN03, CN08, M256 | HEAT-MP-T | Comp-B | 448 MPa | 1130 m/s (L/44) | 24.5 kg | 989 mm | 14.31 kg | 713.32 mm | | K682 (Triple-base) | 600 mm | |
| K280 (XK280) | CN03, CN08, M256 | HEAT-MP-T | Comp-B | | 1400 m/s (L/55) | 23 kg | 998 mm | 11.38 kg | 792.75 mm | 2.1 kg | K684 (Double-base) | | |
Guided munition :
| Ammunition | Compatible tank gun | Type | Filler | Chamber pressure | Muzzle velocity | Ammunition weight | Ammunition length | Sub-projectile weight | Sub-projectile length | Minimum range | Maximum range | RHA penetration | Notes |
| KSTAM-I | CN08 | Terminal guidance | TSCW | | 750 m/s | | | | | 2500 m | 5000 m | | |
| KSTAM-II | CN08 | Fire-and-forget | EFP | | | 21.5 kg | 985 mm | 9.03 kg | | 2000 m | 8000 m | | |

## Export
### 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.

## Operators
### Current operators

* Poland – Polish Land Forces
* South Korea – Republic of Korea Army