I have a KKM 7" and love it. It is incredibly accurate and has been reliable. I just chronographed a load of Longshot and got 1510 FPS from it with a 180 grain bullet. I think you can get slightly more than that with Power Pistol and a 180 grain bullet. The added length is not noticeable for my chest rig. I have a Trijicon RMR on my model 40 it is incredibly reliable and the variable intensity is a real good feature.