It's my understanding that Wilson is now making their own frames . They chose to not have an alloy frame model , whether the frame came from outside or they made it . I don't think they are convinced that a strong enough material has been proven that they want to back with their complete satisfaction policy .
A very famous custom gunsmith has told me that Colt is the only aluminum frame maker who had it right . Les Baer uses another softer grade for their aluminum products, Stinger etc., and according to the smith , it's too soft.
I think Wilson's choice to use an external extractor on the KZ Model was an attempt to cut costs , but recently I heard of the possibility of an internal extractor on that model due to consumer concern . There may be no truth to it as I can find nothing on their website. Either way , they make a reliable gun or they fix it free...Tom