Like alot of the others stated above, get the .357 and the .40 barrel. I have a M&P Compact in .357 along with the .40 barrel . It is my favorite round by far, the trajectory is incredibly flat. You can get 1000 rounds shipped to you door for ~ $400 of the Lawman 125gr from ammoman.com. Use the Lawman .40S&W 165gr as practice as you can pick it up for about $12 a box.