I felt I had to post this and let all potential buyers know that the current Storm Lake barrels are all designed after the older S&W Gen 1 barrel with the collar by the chamber. I bought one and it immediately felt loose in the slide. I took it to the range, and although it shot fairly well. I had numerous failure to feed issues, failure to lock the slide on the last shot at least 5-6 times and one failure to eject. This to me is unacceptable. I emailed Storm Lake and they said they are now going to produce a new version of the barrel, modeled after the later Gen 2/3 barrels with no collar around the chamber. Anyone in the market, I suggest you wait a little bit until they start coming out with the new barrels. They didn't give me a ETA but I told them to let me know when they are in production. If you have an older M&P with the collar, this barrel will work for you, but the later models, this will not.