My M&P Pro rattles like that when shaken. So does my M&P Full Size. My Sheild, not so much.
On my Pro I don't have nearly the amount of slop you seem to have at the muzzle end. On the rear they appear to be the same.
Good luck dealing with S&W. I've sent video's to them in the past. I was told flat out that the "gunsmith's" don't have computers nor the time to look at video's. You will have to get this escalated somehow to get someone to look at the video and communicate with the gunsmith's. It took me two round trips to S&W to have them look at a video concerning sloppy roll pin fit. And in the end I was told that there was no problem as far as they were concerned.
Best of luck. But if I were to place any bets, based on my own past experiences, you'll get your gun back with a nice form letter saying "It's fine".
Lovely, and exactly what I'm afraid of.
I'm really kicking myself in the *** for buying this thing.
