I have recently purchased an M&P 40 and I had a couple of things happen and wanted to know if it is common and will resolve after breaking in. IThe first problem was I had a cartridge jam with rounds in the clip. is this something that will resolve after the pistol breaks in. Also, it was shooting a little low. the range master was watching me and said that he noticed that I was pulling the trigger hard and was pulling the pistol down. I will use a bench rest on my next trip to the range.