Yes, the M&P 9's have accuracy issues. S&W knows this and they have begun to change their barrels. I bought a Pro-Series 4.25 inch barrel last year and it sucked at distances beyond 15 yards. I read this article by Hilton Yam and decided to change my barrel to a KKM precision, which is a drop-in barrel...no smithing required.

25 yard group (10 shots) with factory barrel:



25 yard group (10 shots) with KKM barrel: