Your manual answers this question. The gun is designed to work with +p ammunition. Smith recommends against using +p+ ammunition.
Having said this, I can tell you that the M&P9 was specifically designed with certain +p+ loads in mind and so you are probably fine using ammo manufactured by the Big Three (ATK, Remington, Winchester) marked +p+.
Higher-pressure ammunition will lead to accelerated wear of any pistol compared to standard pressure ammo.
Having said this, I can tell you that the M&P9 was specifically designed with certain +p+ loads in mind and so you are probably fine using ammo manufactured by the Big Three (ATK, Remington, Winchester) marked +p+.
Higher-pressure ammunition will lead to accelerated wear of any pistol compared to standard pressure ammo.