the history of the double action single action?

[ermac]

I've done some googling, but I've never found really any background to what motivated the DA/SA to be created.

[TOrrock]

The Germans wanted a pistol for their police that allowed them to carry a round in the chamber safely but be instantly ready to use without having to disengage the safety.

Walther brought out the PP in 1929 and it took Europe and the world by storm.

[spdldr]

To carry a bit further beyond what Templar mentioned......

The American Colt and Smith & Wesson double action revolvers were becoming quite admired world wide and this was an effort to combine the best of both: the safety and repeat strike on the primer ability (not quite the same as a revolver of course) with the more advanced mechanism of the semi-auto pistol. The ultimate development of this concept that changed military pistols world wide was the P38.

[CAVDOC]

back in the early days of the auto people either carried hammer down on a loaded chamber requiring hammer cock for first shot or empty chamber requiring slide rack and this was seen as a method of overcoming the slow into action issues with autos of the time. the standard of cocked and locked with guns like the 1911 did not become mainstream really until the late 1960's

[ermac]

back in the early days of the auto people either carried hammer down on a loaded chamber requiring hammer cock for first shot or empty chamber requiring slide rack and this was seen as a method of overcoming the slow into action issues with autos of the time. the standard of cocked and locked with guns like the 1911 did not become mainstream really until the late 1960's

What made them want to carry it that way instead of using the thumb safety?

[Dienekes]

Essentially, "administrative" rules--mandating empty chamber carry until use was imminent, for "safety purposes". Most users of semiautos in the early days were large organizations, and they were adverse to NDs. That this carry was less than ideal for the user was not a major consideration to management...

Fairbairn, who was perhaps one of the most forward thinking people out there in those interwar years (Shanghai police--see "Shooting to Live") endorsed this. He taught students to chamber a round as part of the draw stroke. He did get results as per the statistics.

As a product of the 1950s I remember Jeff Cooper's cocked-and-locked approach as being pretty eye-opening.

That's not to say that others didn't employ it, but it was a pretty DA revolver world in those days. The only DA/SA semiautos you saw were bring-back P-38s, half of which seemed to have bad chrome plate refinishes.

[TOrrock]

What made them want to carry it that way instead of using the thumb safety?

The majority of the semi auto pistols available up to that point in Europe, especially 9x17mm and 7.65x17mm (.32ACP) were single action striker fired, which were not especially safe to carry with a round in the chamber.

[spdldr]

Ken Hackathorn is fond of telling me that until they were armed with double action autos, no army in the world allowed its soldiers to holster their pistols with a chambered round. That still may be the case with some countries and or some units who now have the double action weapons.

The idea, I believe, was to prevent NDs by requiring a major and deliberate action to charge the weapon after removing it from the holster. This was a worthy effort, but it's hard to make something fool proof, and impossible to make it damn fool proof.

[CAVDOC]

ermac-
it was a throwback to the way they were used to carrying revolvers- even with double action revolvers the teaching of the time was to cock it to fire to get the lighter easier to manage single action pull,using double action on a wheel gun only in a so called"emergency"
so the idea of carrying a auto the same way is how things got started
in clawsons book on the 1911 several quotes made during the development and testing of the 1911 indicate this was the original intended carry method.
In fact the thumb safety was only added tot he 1911 design at the request of the cavalry to have a method of quickly on safing the 1911 while on horseback so they would not risk discharges from trying to lower the hameer on a bucking horse.
the spring loaded firing pin first showed up in the 1911 design so that it could be carried hammer down with a round in the chamber but without the firing pin in contact with the primer- prior service auto designs from JMB did not have a firing pin spring.
the universal acceptance of cocked and locked as the right way to carry a 1911 did not emerge until the late 60's early 70's

[John Hearne]

My understanding is that the Walther was developed to allow the carry of a loaded pistol in the pocket.

After the Miami Shootout in 1986, most agencies started to transition to semi-automatic pistols. The DA/SA appealed because most agencies didn't trust officers with a SA-style trigger pull. The thought was that after the first shot you were in a gunfight and could be then be trusted with the lighter pull.