I used to be really nervous about using steel cased ammo until I noticed one of my fellow shooters at a steel shoot, who happens to be a gunsmith, happily blazing away with all Russian manufactured, all steel cased ammo out of his Glock 19. True, he is a gunsmith and can fix his own problems, but I figured if it didn't concern him, it shouldn't concern him. Additionally, my CZ-82 (9mm Makarov) has only had steel cased ammo fired through it, and I've never experienced any problems.
Best of luck,
Dave