Daewoo K2

The K2 is an assault rifle of the Republic of Korea Armed Forces. It is manufactured by Daewoo. It is a shoulder-fired, gas-operated, selective-fire assault rifle that feeds from a 20 or 30 round magazine and is chambered for 5.56 NATO. It uses a tough polymer for the forearm, pistol-grip and foldable buttstock. Its bolt carrier group is derived from the American M16 rifle, but the parts are not interchangeable. The gas operating system seems to be derived from the AK-47, and consequently is more robust than the M16. The K2 uses the same magazine as the M16. The barrel rifling has 6 grooves, 1-in-7.3 right hand twist. It is a tough, durable and accurate rifle that is popular with South Korean soldiers.

K1 carbine and K2 rifle
While the K1/K1A carbine is commonly regarded as a carbine version of K2, it is better to consider K1 a separate carbine. Because,
 * The K1 was developed earlier than the K2.
 * The K1 uses direct impingement gas system, while the K2 uses AK-47 style gas piston system.
 * The K1 has 1-in-12 rifling twist for KM193 (5.56 mm) rounds, while the K2 has 1-in-7.3 rifling twist for both the KM193 (5.56 mm) rounds and the K100 (5.56 mm) green tip, full metal jacket rounds.

Variants
MAX-2, AR-100, DR-200, DR-300 are civilan, semi-auto versions of the K2. DR-300 is chambered for 7.62x39mm.