I have two M&P .45's. My first one has always been a little trouble getting the slide off. Now its very difficult to get it off. I have to push and pull and all sorts of things to get it to come off and it's not easy to get on either. I think there is an issue with the slide/receiver fit. My second M&P .45's slide comes right off and on as did my M&P .40. Also when I hold the top of the slide and the bottom of the light rail with two fingers and squeeze I hear a 'clacking' sound like parts are coming together. This does not happen on my other M&P's. It looks like I need to call S&W but they are not open again until 7 Jan. Anyone else seen this? The problematic .45 shoots just fine btw.