Went to the range again with my wife yesterday. We shot another 200 rounds through the 17 round Promag M&P9 magazine and had zero problems. I hear a lot of complaints about Promag. I don't know about their magazines for other guns, but the M&P9 mag seems to work flawlessly. I went to Cabela's yesterday and picked up another 17 and a 32 round magazine. Since the 17 rounders are not available anywhere, these are definitely better than nothing.