Can anyone that owns a GHK AUG take it apart and tell me what parts are composed of at least some iron (probably steel)? I am interested in what exactly GHK is using for materials in the rifle. I know that the outer barrel is some sort of aluminium alloy (a few manufacturers make a steel replacement, however). The frame is plastic, as it is on the real AUG. However, what about the trigger box, bolt carrier, fire selector, and upper receiver (including the integrated scope)?