Steel cased ammo will certainly work. The coating of the steel might prove to be a buildup and subsequent cleaning problem down the road. IMHO, steel will be less accurate than the brass cased because of the better 'obturation' obtained by using brass. The sealing of the chamber and keeping the cartridge in place by obturation is a little known physical phenomena, but has proved to be a significant factor in accuracy and reliability. Why limit yourself in any way while using the 7.62x39 when brass cased ammo is readily available? ...... Big Cholla