The M.S.G Assault Rifles was an exclusive free gift weapon campaign when purchase Frame Arms products over ¥4,000 in Kotobukiyastore and any selected shops in Japan. However, any M.S.G series are not eligible for the campaign according to the official website! Still, it suck to hear it only available exclusively in Japan starting on 22th December 2012. Gosh, I love the design!
See the full kit in action at official blog!