There needs to be a little play in the lock for it to work properly, but it's only a slight back-and-forth play when you move it with your finger(s), all my benchmades have this when closed.

If it clicks and rattles on it's own, I would send it back and have Benchmade look at it. It shouldn't make any kind of noise when you hold it by the handle scales and shake it.


Edit: If you're talking about the click when you open it slightly, that's normal. The design has a natural detent that helps stop the blade from opening in your pocket, so when you open the blade slowly you'll hear two clicks. The first is overcoming the detent, the second is the lock engaging.