After firing around 100 or more rounds through my M&P performance center ported 9mm and it gets hot from firing, you may pull the trigger and nothing, or you may have to pull it a couple more times before it fires..... not good, not safe, but it has to get hot before this occurs......will even do it just dry firing it until it cools down. Is the porting causing a problem somehow...?? Thanks.........Help.....
Have you contacted S&W about the problem? There may be a known issue with guns in your serial # range.
Speculation on my part, but the gun may not be closing fully (stays disconnected) on the hot barrel, particularly if the barrel is at the large end of the spec. to begin with.