I was wondering what would be more effective, the 45 acp would only be moving around 650 fps and the 9mm around 1000 fps. Those are only educated guesses. I have a XDS in 45 but i am thinking about getting it in 9mm when it becomes available. The extremely low velocity of the 45 out of such a short barrell has me questioning its effectiveness. Wanna kill these ads? We can help!