I think Mike Raso has a pretty good reputation when it comes to his stuff. I really doubt he would sell a dud camera. Like the guys said, you need to keep the button pressed until you hear the second click of the lens. Also, the cocking mechanism needs to be pressed fully. On my Polaroid 315, there is a double step in the shutter cocking lever. If you bring it to the first, it won't work. You have to press slightly harder to get to the second click which feels positive.