anyone know of any actual problems resulting from shooting steel rather than brass cased in a bolt action?
Only thing I can think of offhand is that some have reported that some Steel case ammo that was intended for use with LMGs has a laquer coating that when it got hot from sitting in an already hot chamber would soften , and after the chamber and laquer cooled it would glue the case solidly in the chamber. Getting the case out after the chamber cooled was quite an undertaking.
I believe this was mentioned as a common problem with some German made 7.62 Nato LMG ammo that had been de-linked. That particular laquer coating may be why the ammo was sold off as surplus. It would cause no real problem in guns that fire from an open bolt, but could jam up a G3 pretty easily and/or fill in the chamber flutes to further hinder smooth extraction.
On the upside some long range target shooters have experimented with making cartridge cases with a brass body and a steel casehead, to allow use of chamber pressures that might make a brass casehead cold flow.
I don't think a steel case would be totally immune to casehead cracking, but its unlikely to cold flow at any sane chamber pressure.