Someone here did a study that I remember quite well on how long steel cases last as opposed to the brass in normal reloading and found virtually no difference. I reload steel in 7.62x39 regularly. I do find a cracked case here and there but I generally shoot more 7.62x39 than any other round as all those rifles are high capacity semi's and my others are mainly bolts. No problem here if you are inspecting as you should any case.