I recently bought a Performance Center 9mm Shield and now have the same problem with the takedown retaining wire. Happened after my second range day with it. It's now back at my dealer for their gunsmith to figure out. If he can't fix they'll send it to S&W. This is my first polymer frame pistol and it's not giving me much confidence. I have five 3rd generation S&W's and have had zero problems with all. In the meantime I'm sticking with my 3913.