Steyr Mannlicher phoned me from Austria today.
We were discussing spare parts issues, etc...
The extractors and extractor springs on certain "Early" model pistols (I do not know how "Early" is defined") were fitted with "weak" extractor springs that caused problems.
The new replacement parts have been upgraded and come with a stronger spring and a new extractor.
Keep this in mind. I am going to order one for my M9 just to be sure. I don't know when they made the change at the factory, in terms of serial numbers or production dates. I will try and find out.