The AK-47, officially known as the Avtomat Kalashnikova (Russian: Автома́т Кала́шникова, tr. Avtomát Kaláshnikova, lit. 'Kalashnikov’s automatic device'; also known as the Kalashnikov and AK), is a gas-operated, 7. 62×39mm assault rifle, developed in the Soviet Union by Mikhail Kalashnikov. It is the originating firearm of the Kalashnikov rifle (or "AK") family. 47 refers to the year it was finished.