In Israel they are not allowed to carry a round in the chamber. For this reason, Massad and Israeli police developed a way of placing the gun behind their back where they can reach it with the gun hand and as the pull it around to the side they rack it with the other hand giving them almost as much speed as a bullet in the chamber.
Interesting!
This is not just a tv gimmick, it is now widely used in other countries since America is one of the few countries that carry their guns chambered and keep their finger on the outside of the trigger guard (after all your finger is your only safety) and if you will notice military pictures show the same method of holding any type of assault weapon. Finger outside the trigger guard until it is pointed and shot.
I always have a round chambered, and 13 additional rounds in the magazine.
Obviously, if you carry a gun with a chambered round, you don't need to rack the gun from you back and shoot from the side.
Slightly off topic, I find it really funny how so many of the Hollywood folks either don't understand how guns operate, or they assume the general public doesn't know how they operate.
I was watching a show the other night where a man was being threatened by a handgun held to his head. In order to ratchet up the dramatic tension, the actors usually pull back the hammer on what is a DA/SA pistol in order to give the handgun more of a "hair-trigger." That's fine, because it is fairly realistic. Well the other night, the bad guy had the gun to the hero's head and actually manipulated the entire slide(!), thereby chambering a round. Since a round was not ejected when he did that, the bad guy was apparently holding a gun without a round in the chamber to the head of the hero as some kind of threat (talk about incompotent). Furthermore, it didn't sound like he had actually transferred a round from the magazine into the chamber. Expecting a plot twist, I told my wife, "the guy is bluffing with an unloaded gun." Alas, it he was not. Just another Hollywood misrepresentation.
My favorite TV/movie gun cliche is holding the semi-auto pistol sideways ("the death shot") to shoot. Try that on a real pistol and you are likely to stove-pipe or otherwise jam it since the brass may not eject properly.