High Quality Content by WIKIPEDIA articles! The AK-107 is a Russian 5.45 mm assault rifle developed from the AK-100-series. It features a "balanced" operating system, similar to that used in the AEK-971. In this case, the designation AK does not indicate Avtomat Kalashnikova but Alexandrov/Kalashnikov. The revised designation indicates the incorporation of a new gas system, designed by Youriy Alexandrov, for Kalashnikov-pattern rifles.