[Mauser720]

Perhaps another reason: The Luger is the only pistol design I am aware of in which a significant amount of mass is forced upwards as a part of the semi-automatic ignition process. (the front and rear toggles, and the three pins associated with these parts) The physics involved in this upward movement must result in a tendency to tame the recoil, and return the barrel to point of aim much quicker. If there is another design that does this, I am not aware of it. Every other design involves mass (parts) moving directly backward. The Luger is a very clever design.