while doing some searches on the korean barrels i came across an interesting hybrid project.
someone modified a 22caliber daystate air ranger and instead he fitted a .20sumatra barrel that shot excellently with the 24 grain korean pellets. he seems pretty happy about the conversion.
the thread was found on the yellowforum named as"Air Ranger / .20 cal Sumatra hybrid / 102 yards"

there are some good photos of the groups and the article relating how the conversion was possible.

2) does anyone know who sells korean barrels independently? i had read some posts about people buying these but never got where they bought them from.