Sorry that it appears I am necroing this thread, but I'd rather that than create my own thread based off of a single question that is easily answered.
Anyway, what parts are steel?
I am certain the entire receiver, trigger guard, and flash hider is steel. What about the carrying handle? Is it potmetal or steel? What about the folding front sight unit? Steel as well?
I really hope those two parts are not potmetal or some kind of cheap aluminium. That wouldn't be fun...