I know all this has been posted before, but here it is, all in one post. These are just the facts, not opinions, or expressions of what one might "be comfortable" with.
Turning the manual safety ON on a Walther PP-series pistol does three things:
1) If the hammer is cocked, it drops the hammer to the decocked position which then requires a double-action pull, or manually re-cocking the hammer to fire;
2) The safety drum rotates around to positively lock the round knuckle on the firing pin, which prevents the firing pin from moving, and
3) Shoulders on the safety drum are rotated around to shield the rear tip of the firing pin from any contact from the hammer. This provides additional protection against a possible AD arising from a fracture of the locked firing pin or of the safety drum itself -- which occasionally happened with wartime P38s.
The last two are important for the purposes of this post. Unless you turn the manual safety ON, the firing pin is neither locked nor shielded. If the gun is dropped on its muzzle, the inertial firing pin may move forward to strike a chambered cartridge. If the gun is dropped on its tang and hammer, the slide may fly rearward, carrying the firing pin with it, to strike the hammer; the pin can then bounce forward to strike a chambered cartridge. This is not theoretical; it has happened.
In these scenarios, the automatic hammer block is not involved, and cannot prevent either kind of AD.
It should be remembered that the PP-series were state-of-the-art in 1929. However, it has no automatic passive firing pin lock; the device might not even have been invented then. But this is 80 years later, and gun designers have learned a thing or two since.
Many folks express great confidence in the quality of their holster to prevent an accident. While a few in-holster ADs do occur, most drop-fires occur after the gun has been removed from the holster, and the style and type of the holster is irrelevant.
Comparing the PP-series with the safety OFF to a P99 or similar pistols which have no manual safety is comparing watermelons to cucumbers. Most service autoloaders designed since about 1980 have internal passive firing pin blocks that immobilize the firing pin until the trigger is pulled. These are not foolproof either --as the parts are small and easily impaired, depend for reliable operation on a tiny spring, and their functional status is inconvenient to verify--but they are better than no firing pin lock. Today no responsible manufacturer would consider introducing a fresh design of autoloading pistol that did not incorporate an internal passive firing pin block. The Walther PP-series, like the M1911, are anomalies; they remain in production only because there is a demand for a few "classic" designs.
Comparing PP-series with the safety OFF to double-action revolvers that have no manual safety is similarly misguided. They are mechanically not comparable.
All double-action revolvers made by the major manufacturers (Colt, S&W, Ruger, etc) during the past 100 years have lockwork that physically interposes a block between the hammer and the frame to prevent firing until the trigger is pulled through. Inertial firing in a revolver is not a concern; most revolvers have the firing pin riveted to the hammer; if the hammer itself is blocked, so is the pin. Even when separately mounted in the frame, a revolver's firing pin is tiny, and by itself is too light to detonate a primer. Nor does a revolver have any reciprocating mass comparable to an autoloader's slide that might move hard enough or far enough, carrying the firing pin with it, to generate an AD. Basically, revolvers fire from dropping only if something breaks or, for a multitude of reasons including home gunsmithing, doesn't work as it should.
The case of the 1911 service pistol is perplexing. When dropped on its muzzle with the safety OFF, it will NOT fire as commonly supposed. The slide will break open and tilt down the barrel before the firing pin can hit a chambered cartridge in the center. That is obviously marvelous, but a different result is obtained if the safety is ON, which is anti-intuitive. Conversely, if the gun is dropped on its tang and/or hammer, the risks are reversed: Safety OFF is probably more dangerous as it allows the slide to move rearward; with the safety ON, the slide is locked. Bottom line: whether it's better to have the safety ON or OFF if the gun is dropped depends on how it lands.
All this, of course, is predicated on dropping the gun only once. Often guns survive one drop and fail after the second or third. The basic problem is that in any handgun small and light enough to be conveniently carried and used, it's very difficult to make the parts big and strong enough to withstand the enormous structural stresses imposed by dropping the gun onto hard surfaces like concrete or steel, and it becomes practically impossible when the stress is repeated. This can be documented: read the H.P. White Laboratory handgun torture tests done in the 1970s. (There was a REASON why SIG cut a slot in the hammers of later P6 police pistols. To put it politely, they concluded that German cops were clumsy.)
BTW, how many lives have you cats used up?
M
Turning the manual safety ON on a Walther PP-series pistol does three things:
1) If the hammer is cocked, it drops the hammer to the decocked position which then requires a double-action pull, or manually re-cocking the hammer to fire;
2) The safety drum rotates around to positively lock the round knuckle on the firing pin, which prevents the firing pin from moving, and
3) Shoulders on the safety drum are rotated around to shield the rear tip of the firing pin from any contact from the hammer. This provides additional protection against a possible AD arising from a fracture of the locked firing pin or of the safety drum itself -- which occasionally happened with wartime P38s.
The last two are important for the purposes of this post. Unless you turn the manual safety ON, the firing pin is neither locked nor shielded. If the gun is dropped on its muzzle, the inertial firing pin may move forward to strike a chambered cartridge. If the gun is dropped on its tang and hammer, the slide may fly rearward, carrying the firing pin with it, to strike the hammer; the pin can then bounce forward to strike a chambered cartridge. This is not theoretical; it has happened.
In these scenarios, the automatic hammer block is not involved, and cannot prevent either kind of AD.
It should be remembered that the PP-series were state-of-the-art in 1929. However, it has no automatic passive firing pin lock; the device might not even have been invented then. But this is 80 years later, and gun designers have learned a thing or two since.
Many folks express great confidence in the quality of their holster to prevent an accident. While a few in-holster ADs do occur, most drop-fires occur after the gun has been removed from the holster, and the style and type of the holster is irrelevant.
Comparing the PP-series with the safety OFF to a P99 or similar pistols which have no manual safety is comparing watermelons to cucumbers. Most service autoloaders designed since about 1980 have internal passive firing pin blocks that immobilize the firing pin until the trigger is pulled. These are not foolproof either --as the parts are small and easily impaired, depend for reliable operation on a tiny spring, and their functional status is inconvenient to verify--but they are better than no firing pin lock. Today no responsible manufacturer would consider introducing a fresh design of autoloading pistol that did not incorporate an internal passive firing pin block. The Walther PP-series, like the M1911, are anomalies; they remain in production only because there is a demand for a few "classic" designs.
Comparing PP-series with the safety OFF to double-action revolvers that have no manual safety is similarly misguided. They are mechanically not comparable.
All double-action revolvers made by the major manufacturers (Colt, S&W, Ruger, etc) during the past 100 years have lockwork that physically interposes a block between the hammer and the frame to prevent firing until the trigger is pulled through. Inertial firing in a revolver is not a concern; most revolvers have the firing pin riveted to the hammer; if the hammer itself is blocked, so is the pin. Even when separately mounted in the frame, a revolver's firing pin is tiny, and by itself is too light to detonate a primer. Nor does a revolver have any reciprocating mass comparable to an autoloader's slide that might move hard enough or far enough, carrying the firing pin with it, to generate an AD. Basically, revolvers fire from dropping only if something breaks or, for a multitude of reasons including home gunsmithing, doesn't work as it should.
The case of the 1911 service pistol is perplexing. When dropped on its muzzle with the safety OFF, it will NOT fire as commonly supposed. The slide will break open and tilt down the barrel before the firing pin can hit a chambered cartridge in the center. That is obviously marvelous, but a different result is obtained if the safety is ON, which is anti-intuitive. Conversely, if the gun is dropped on its tang and/or hammer, the risks are reversed: Safety OFF is probably more dangerous as it allows the slide to move rearward; with the safety ON, the slide is locked. Bottom line: whether it's better to have the safety ON or OFF if the gun is dropped depends on how it lands.
All this, of course, is predicated on dropping the gun only once. Often guns survive one drop and fail after the second or third. The basic problem is that in any handgun small and light enough to be conveniently carried and used, it's very difficult to make the parts big and strong enough to withstand the enormous structural stresses imposed by dropping the gun onto hard surfaces like concrete or steel, and it becomes practically impossible when the stress is repeated. This can be documented: read the H.P. White Laboratory handgun torture tests done in the 1970s. (There was a REASON why SIG cut a slot in the hammers of later P6 police pistols. To put it politely, they concluded that German cops were clumsy.)
BTW, how many lives have you cats used up?
M