You know, it may not be your wrists at all. Jamming seems to be a problem that is consistent through the Walther family. The British Secret Service discarded the Walther because they believed this to be true. In fact, they claim that in only jams when you need it the most (in combat). I hear they actually switched to Berrettas in the 80s.
I myself have run into this from time to time. My cousin says that Walthers are cursed. (I don't believe him, but sometimes I worry...)I just love the feel of the Walther, and can't seem to give them up.