"The Guard Post" is a Korean movie involving story of a mysterious death of an entire platoon located at Guard Post 506 (GP506) near the DMZ, a border between North and South Korea.
The following weapons were used in the film The Guard Post:
The Daewoo K2 is the weapon that is shown the most in the film, and is used by all Korean infantry soldiers in the movie. It is the main assault rifle of the Republic of Korea Army. The weapon is seen with both rail system and optics on and without. Almost all of the optics and rails used are manufactured by the Korean Dong-In Optical Co.
Ja-Seng K2 airsoft replica
When the actors aren't firing blanks, they are mostly seen with Ja-Seng K2 airsoft replicas, which would be much lighter and safer for the actors to handle, and can be used without an armorer present on the set. The difference from the actual Daewoo K2 rifle can be seen by the straight bolt-handle, smaller rear-sights, awkward-shaped folding-stocks, thinner front-sights, lower bolt placement, smaller bolt, gap between the receiver and the hand guard, and the lack of swing swivels on the lower barrel.
Trivia: The Ja-Seng K2 airsoft replicas are all-plastic, scaled-down, pump-action airsoft replicas. They are known for their bad quality: lacking bolt, smaller scale, and bad details. It is quite amazing how the prop-designers of this movie improved the quality of these airsoft replicas up to this much.
Dong-San K1
Dong-San K1, airsoft replica of the Daewoo K1A, is seen carried by several soldiers in the film but is never seen up close or being fired. The difference from the actual Daewoo K1A can be seen by the lack of take-down lever behind the rear-sight, square pistol grip, larger and rounder trigger guard, higher bolt placement, straight bolt-handle, and the lack of magazine fence.
Daewoo K5 (DP-51)
The Daewoo K5 pistol is seen carried mostly by Sergeant Major Noh and Staff Sergeant Yoon. It is also seen in the flashback in a fight between First Lieutenant Yoo and the medic, where Yoo uses it to shoot the head of the medic.
Fake M60
A mocked up M60 machine-gun can be seen when Corporal Kang is explaining about the North Korean GP 300 meters away to two newcomer privates. He accidentally discharges the weapon, which results in a burst of machine-gun fire from the North. Corporal Kang shows the M60 to the newcomers, calling it as the machine-gun that came out in the movie "Rambo". However, this M60 seems to be a fake M60 with front-sight taken from AR-15 series and a thick cylindrical part of the barrel sticking out of the hand guard. The gun also apparently fires from a closed-bolt position, where as actual M60s fire from an open-bolt position. It also apparently does not eject ammunition belt links when it fires. It is unsure, however, what the base-weapon of this M60 mock up is.