Excerpt from American Handgunner, Author Masaad Ayoob:
In the Midwest, a gun shop owner was disarmed of his HK P7 and herded into a back room of the shop, where he was certain the two robbers would execute him. He grabbed a concealed S&W .357 Magnum revolver and spun on the man who was leading him to his death at gunpoint. The robber pulled the trigger of the German squeeze-cocker pistol, but nothing happened. The storeowner began pulling his own trigger. Sometimes his revolver just went "click," and sometimes it roared with Magnum force. The first man fell. The gun dealer kept pulling the trigger, now engaging the second perpetrator, until the man fell dead.
Lessons: The unique design of the HK P7 pistol requires the cocking lever on the front of its grip-frame be firmly depressed for the pistol to fire. Thankfully, the bad guy in this case wasn't holding it firmly enough, and was unable to carry out his murderous intent before the good guy killed him and his equally homicidal partner in crime. The revolver had been in perfect working order except for having been fitted with lighter-than-factory springs in hopes of gaining an easier trigger pull. Fortunately, the good guy's many pulls of the trigger yielded enough successful primer ignitions to win the fight. It can be a life saver to have a gun that is "proprietary to the user," that is, which the legitimate user knows how to swiftly bring into action, and a punk who grabs the gun probably does not. Moreover, the light trigger pulls desired by target shooters can, and often do, compromise the reliability so desperately needed in a true defensive weapon.
In the Southwest, a well-intentioned good guy who was apparently a little ambivalent about his choice, decided to carry a gun. He purchased a Glock 23 and kept it in a fanny pack, loaded with a magazine of .40 S&W training ammunition but with nothing in the chamber.
The day came when he was faced with armed robbers. He grabbed the Glock out of the fanny pack and tried to chamber a round. but fumbled with the slide and jammed his pistol. The robbers shot him down. He survived--and sued Glock, Incorporated.
http://findarticles.com/p/articles/mi_m0BTT/is_167_28/ai_110457294/
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There you go, a REAL WORLD incident of a man who is not dead because his primary firearm was a P7. In this incident, if the Law abiding citizen is carrying a Glock, a Sig, or a revolver....he's dead.
People just don't squeeze the FRONT of the gripframe that firmly as a natural instinct (most pressure is applied to the grip panels in a typical handhold). It takes a
deliberate amount of force -26lbs- to activate the single action mechanism of the P7. IOW, you have to
know to do it.
The robber in the above story did not know...and now he's dead, and the owner of the P7 is not.