First of all, THERE IS NO AK-47 RIFFLES. There is only AK, without "47". The first AK model was created in 1947, GRAU index 56-A-212, in service from 1951 to 1974 (the next 5.45mm model AK-74 was created in 1974).

And as said in GRAU (The Main Missile and Artillery Directorate of the Ministry of Defense of the Russian Federation), AK is an assault riffle or an automatic carbine riffle.