I found this by Googling M&P torture test...
pistol-training.com » Blog Archive » M&P Monday: Week Thirty-Three
It seems these guys put over 62,000 rounds through an M&P9 and had a broken trigger spring after 20,000+ rounds, then the slide lock lever broke off on one side but the gun didn't care and kept firing, then at 62,000 rounds the slide developed a crack. The gun continued to fire for the day and then was sent to S&W who examined it and said it is still fine to shoot, but some lawyers decided to end the torture test.
These guys would get the gun so hot it was hard to hold. They wouldn't clean it regularly. They really tortured it. And at 50,000 round sit still shot a 1 1/4" pattern at 25 yards.... Wow.
EDIT: Forgot to mention they had two failures to function that they determined were from over greasing the action. These were very early in the test (week 6). Once they quit greasing the action heavily the gun performed flawlessly for the next 50,000 or so rounds. No failures to extract. No replacement parts. No failures to fire.