I had an almost brand-new M&P 40 full size blow up. The cause was a 9MM round in a brand new box of Winchester Ranger .40 S&W's. I sent an email to Winchester that night. I also sent one to Smith & Wesson, who asked me to send the gun back to the factory for examination. I sent the gun to Smith, they confirmed that there was a Winchester 9MM cartridge case stuck in the barrel. The gun fired the 9mm then failed to eject the case. The incoming .40 round jammed the 9MM case into the barrel and when I pulled the trigger - KaBoom. The light rail/bottom of the frame was completely gone (indoor range and couldn't even find a piece of the frame). I did find a 3 inch section of the barrel that blew out. Through the hole in the bottom of the frame, you could see the fired bullet, in the end of the barrel you could see the empty 9MM case. It was very clearly the fault of Winchester for putting a 9MM round in the middle of a box of .40's. I should have caught it when I loaded the gun. I really never expected a 9 in a box of 40's. Smith and Wesson, even though they knew that they were not in any way at fault, replaced the pistol for $270, basically dealer cost (and not a small dealer, at that). This, at a time when these pistols were selling for over $400.00 on sale. I, personally, consider that to be customer service above and beyond what I would have expected. I have numerous witnesses and pictures of this whole case, from beginning to end. In my communications with Winchester, all they wanted was my doctor's bills. There were no doctor bills, since the Smith was so well designed that everything blew away from the shooter. I also have a M&P 9MM that I bought after this affair, and that thing is a tack driver. I shot it back to back with a stock Glock, a SIG, and a custom Glock with a extended, ported barrel. The stock Smith shot rings around the others. I have no problem with Smith and Wesson, but I didn't buy my extra mags from the factory, so I can't comment on that.