This is not military, but it's widely advocated in the concealed carry community that you should carry with one in the chamber. The argument is that with modern pistol designs and the right precautions, it's generally safe; and that many scenarios where you might need to defend yourself need all the possible speed you can get. Having to stroke your firearm to load it can easily add 2 seconds to your draw.

That said, given all the stories I've read, I can't imagine carrying a P320 with one in the chamber.