The Japanese development is important. They only had Akome iron sand instead of the standard iron ore. Yet because of the ama-no-habuki bellows, which unlike western bellows, allow more oxygen, thus a hotter forge. They were able to reduce the impurities and became masters at controlling the hardness of the metal.

There is much theorizing today that wootz steel was dependent on impurities found in the local ore scource.

The fall of Vienna was a waterfall event for European gun makers. Eventually all military technology finds it's way into the private sector.

Pete