Sounds like the inside tenon of the slide lock broke or got chipped, or maybe the detent plunger is not holding the lock firmly in the slide.
Is this where we rehash the whole MIM topic again? It's been weeks!
More like hours,http://www.downrange.tv/forum/index.php?topic=16053.msg206258#msg206258
Have you fired it? What's it like? How does it compare to the Ruger LC9?Richard