what caliber are/ak
5.45x39 is the caliber of the AK-74, and copies such as the North Korean Type 88, Polish Tantal, and others. Many variants exist in 5.56x45, including the Russian AK-101, Chinese Type 84, variants of the Bulgarian AR-M1, export variants of the Finnish Rk.62/76 (these were also the basis for the Israeli Galil rifle), Yugoslav M80 and M21, etc.