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Discussion Starter #1 (Edited)
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
 

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Mike, good post and good explanation.
Now, all that considered, is it safe to handle a loaded PP on a firing range? The gun is loaded, safety off, and the holster doesn't matter...? All the ranges I use have a concrete firing line.

Really not trying to be a troll here; hell, I love Walthers and have a lot of respect for Mike's vast font of knowledge. But if they are that big a risk to handle loaded and unsafed, should we be decocking and applying the safety between shots at the range? Is it prudent to handle one that is loaded and ready to fire under any circumstance?

In a self defense situation, are we ethically obliged to keep the safety on until the instant we're about to pull the trigger?

Interesting thoughts about the 1911 pistol as well, tho' some of the issues have been addressed in more recent production.

In dealing with all things mechanical, there is a certain level of implied risk, whether driving a car or a nail, or carrying a gun. Where we step over the line from prudence to recklessness is a hard call. I think we need to be aware of a worst-case scenario, but we have to be careful that we don't immobilize ourselves with excess caution.

Just sayin'
Moon
 

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Discussion Starter #4 (Edited)
...
Now, all that considered, is it safe to handle a loaded PP on a firing range? The gun is loaded, safety off, and the holster doesn't matter...? All the ranges I use have a concrete firing line.

... But if they are that big a risk to handle loaded and unsafed, should we be decocking and applying the safety between shots at the range? Is it prudent to handle one that is loaded and ready to fire under any circumstance?

In a self defense situation, are we ethically obliged to keep the safety on until the instant we're about to pull the trigger?

...
Moon
Moon: You've asked a thoughtful question. I think all gun handling is ultimately reduced to a risk-benefit calculation, and since both risk and benefit are subjectively determined by the user, there is no objectively correct answer. Sometimes the answer changes with hindsight. In other scenarios practical observation and experience can provide some guidance. In each instance the user must balance the level of danger inherent in what he is doing against the benefit that the action provides. That benefit includes the enjoyment of a tool's utility. We do this every day in all aspects of life, not just with guns.

So is it "too risky" to handle a loaded PP with the safety off at a range? I've never thought so. Once I have the gun IN MY HAND, I am not particularly concerned about dropping it. And my finger is outside the trigger guard, so any danger of accidentally actuating the trigger is relatively remote. Obviously I don't put the safety after every shot (no reason to) but if I have to run with it to another position as part of a drill, I will (because there is some risk I may trip and fall).

It's when the gun is NOT in my hand that I start seriously recalculating the risks. Most drop-fires and other ADs occur when people are "carrying" the gun or "handling" it, or they are just "sharing space" with it --not actually using it to shoot. That's when you need to be realistic and recognize --and take sensible precautions against-- the multitude of things that can easily result in an AD. I don't want to be the guy whose moment of inexplicable carelessness turned some innocent bystander into a quadriplegic.

M
 

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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.
S&W didn't drop proof the pistols till 1945 . Till then was a chance. I learned this as I bought a old S&W . Its serial number was strange . When I checked with S&W they told me that showed first year of hammer block . Was made 1945 . My oldest S&W is 1880 I belive it will fire if hammer hit .
 

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One of the most clearly written physical descriptions of a system I've ever seen. Bravo, Mr. Mike. This forum has greatly benefited from your knowledge and experience. You're like The Professor here!

Class in session!

-Pilotsteve
 

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I am curious. I have searched for documentation regarding dropped AD of the PP, PPK, and PPK/S pistols and can find none. I agree that whether or not the safety is on does not matter for a dropped PP variant unles the hammer is released (which would not be the case with the safety on).

If a pistol is dropped from the average belt height of a six foot man the pistol would travel three feet. In our atmosphere a normal solid object can travel that distance in about one second. Upon an absolutely perfect impact (firing pin channel perfectly perpendicular to the ground), the weight of the firing pin (I am guessing about 1/3 ounce, you do not calculate the weight of the pistol as that has no bearing on the outcome) traveling for one second at 32 ft/second squared would only have a force of .6 ft/lbs and that is at the forward portion of the firing pin, not at the primer. The firing pin spring would add resistance to that greatly reducing any impact to the primer, especially considering the distance the firing pin would travel on impact and that when a spring is compressed it exerts greater resistance directly proportional to the amount of compression.

On the other hand, a hammer exerts energy based upon the square of the hammer mass times its velocity divided by two. To keep things equal, if a one ounce hammer were travelling at the same velocity as the falling pistol (even though the hammer travels much faster) the energy released at the time of hammer/firing pin impact is four times that of the aforementioned falling firing pin. Because there is a direct transference of kinetic energy from the hammer to the firing pin (Newton's third law) the firing pin would move with four times the force thus easily overcoming the spring and striking the primer.

If we knew an overall average between blued and stainless firing pins and hammer weights plus the speed the hammer is actually moving when it impacts the firing pin I could provide exact figures. I would also need to know the average exponential spring compression force exerted by the firing pin spring.

I have a feeling that a pistol as successful as any PP variant has had the engineers examine it thoroughly to ensure these tolerances exceed safety requirements.

Regardless, I feel completely safe carrying any of my PP variants with a round in the chamber and the safety engaged.
 

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Discussion Starter #8 (Edited)
S&W didn't drop proof the pistols till 1945 . Till then was a chance. I learned this as I bought a old S&W . Its serial number was strange . When I checked with S&W they told me that showed first year of hammer block . Was made 1945 . My oldest S&W is 1880 I belive it will fire if hammer hit .
The lockwork I referred to was introduced in both S&W and Colt revolvers around 1905. It prevented firing in the vast majority of drops, but it certainly was not "drop-PROOF". During WWII, after a fatal accident aboard a ship in which an S&W revolver fell onto a steel deck and fired, a further improvement was introduced, which is still used in S&W revolvers today. But even that is not 100% "proof" against extreme stress or repeated drops, as the block can be mashed wafer-thin and ultimately firing can result. That is not a defect; it merely illustrates the near-impossibility, even with modern materials, of producing parts that are small enough for practical use, yet strong enough to withstand the extreme stresses of high drops on steel or concrete. It simply can't be done, at least not within the state of the art today.

M
 

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Also, the HP White laboratory tests drop the pistols from a height of 42" in a controlled test so that the pistol will fall exactly on its barrel, right side, left side, bottom, top, and on the hammer.

The tests are also conducted repeatedly to include any variations of the pistol configuration (safety on, safety off uncocked, and safety off cocked).

I did a thorough search and could not find published test results online indicating any failures.

In reference to one of Mike's comments, dropping a small arm like the PP variant repeatedly will provide little other than cosmetic damage to the pistol. In order to damage internal components the pistol would need to be seriously abused way beyond what any normal person would do. These were in fact designed for police and military use. Explosions go off inside them repeatedly (which exerts much greater force on the internal components than dropping them) and after thousands of such explosions they still will function as designed.

Also, only older revolvers of the major manufactuerers have firing pins connected to the hammer. For the past thirty years there is a flat hammer with either a firing pin transfer plate or a hammer block that allows the energy from the hammer to transfer to a firing pin in the frame just like an autoloading pistol. Those are considered safe to carry a round under the hammer.
 

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Discussion Starter #10
Also, the HP White laboratory tests drop the pistols from a height of 42" in a controlled test so that the pistol will fall exactly on its barrel, right side, left side, bottom, top, and on the hammer.

The tests are also conducted repeatedly to include any variations of the pistol configuration (safety on, safety off uncocked, and safety off cocked).

I did a thorough search and could not find published test results online indicating any failures.

In reference to one of Mike's comments, dropping a small arm like the PP variant repeatedly will provide little other than cosmetic damage to the pistol. In order to damage internal components the pistol would need to be seriously abused way beyond what any normal person would do. These were in fact designed for police and military use. Explosions go off inside them repeatedly (which exerts much greater force on the internal components than dropping them) and after thousands of such explosions they still will function as designed.

Also, only older revolvers of the major manufactuerers have firing pins connected to the hammer. For the past thirty years there is a flat hammer with either a firing pin transfer plate or a hammer block that allows the energy from the hammer to transfer to a firing pin in the frame just like an autoloading pistol. Those are considered safe to carry a round under the hammer.
It's a free country...

M
 

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Early centerfire revolvers were made safe by lowering the hammer on an empty chamber, but the notion of a 'rebounding' hammer came along in the 19th Century. Rebounding hammers retreat from the full forward position when the trigger is released. Smith 'Lemon squeezers', an early effort at a foolproof revolver, had a rebounding hammer, a grip safety, and a trigger pull from hell. Later Smith revolvers (say, an '05 M&P) had a rebounding hammer which was prevented from going forward if struck by a protrusion on the hammer which interfaced with another raised area on the rebound slide, which is linked with and powers the trigger. As long as the trigger is forward, the hammer is held away from the primer...unless, as Mike noted, the thing was dropped from a great height, landing hard enough on the hammer to break the hammer axle. This is a 1/4" stud pressed into the left side of the frame and supported on both ends; the hammer turns on it. To prevent this from reoccurring, Smith went to a hammer block that is cammed out of the way by the rebound slide when the trigger is pulled.
Unless some fool is determined to play the drum solo from 'Gadda da Vida' on the hammer spur with an 8oz ball peen, I find it hard to picture how the hammer block could be beaten 'paper thin'. Sorry, Mike, but that's a reach and not likely to occur in the real world, especially since the old system of blocking hammer movement with the rebound slide is still in place on current Smith production.

I also recall the HP White lab tests, but don't recall the results. Either they were favorable to the guns tested, or the NRA/gun industry put the kibosh on them. The administration at the time (Kennedy? Johnson?) wanted to identify 'unsafe' guns (Saturday Night Specials?) as contrasted to quality firearms, as a means to ban the former. Again, as I recall, the current arrangement where the Consumer Product Safety Commission has no say about firearms is related to this issue. The concern, of course, was that the CPSC could ban every gun with the stroke of a pen, claiming it 'unsafe'.

I'll be interested in reading some more of Iron Man's physics; it does seem that you would have to be living really wrong to get a discharge when dropped from waist height. The Bond movie where James manages to fumble his gun and drop it several stories is a more believable scenario. Some pistols now use a titanium firing pin; its light weight makes an inertial discharge about impossible even if the gun was dropped from Mars. What I would really like to know is just how great the risk actually is with a traditional steel firing pin without a block. It may well be that the gun industry is just covering their derriere.
Moon
 

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Discussion Starter #12 (Edited)
I have been spending 'way too much time on the forum in the past week because I have been sick in bed and didn't feel like doing much of anything else. But I am now feeling fairly human again and have to return to more productive pursuits.

For that reason I am going to make an exit from point-by-point refutations and extended discussions of everybody's theories and opinions -- some of which, at least, seem to be based from what can or cannot be found on the internet.

What I have written in this and other threads recently regarding drop-firing and other mechanical failures are not figments of an overactive imagination. They are drawn from knowledge of real-life testing and actual incidents that have occurred. You are all free to take caution from them or not as you please.

Anyone interesting in pursuing the topic would do well to first sit down and study the test procedures and criteria of SAAMI, the BATF, the H.P. White Laboratory and the German Police Academy (which are all different). That's not everything one needs to know, but it's a start.

M
 

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Mike,

I am not attempting to argue or insult. I am curious about the tests so that I can read them as I could not find the test results online. I was simply saying the physics don't make sense. Almost all handgun manuals caution against dropping a loaded firearm. However, for a small firing pin to gather enough momentum to overpower the spring and still set off a round would require a much greater than average height.

I responded in the middle of the night and where I live published research from firearm testing companies are not readily available even during normal hours.
 

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I'd heard of the use of titanium firing pins as a method of reducing the mass (and therefore the inertia) in the case of a dropped firearm. Seemed a bit hokey in my first impression. Such a tiny piece of metal can't have much of a difference in weight.

Titanium has a density approximately 60% that of steel though. (I say approximately, since I don't know what alloy of Ti is used, and "steel" is an alloy of iron. I used Ti metal and medium carbon steel. Reference Online Materials Information Resource - MatWeb for data.) Regardless, it is a significant difference in density. I'd expect a proportional reduction in impact energy at the primer.

Just a few rambling thoughts...
 

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MLB, I have a couple pistols with the Ti pins, and they have worked just fine; impact on primers does not seem affected. It seems a more elegant solution to me than the numerous linkages and plungers (with their attendant possibilities for mischief) necessary for a firing pin lock. As I noted, said linkages can have an adverse effect on trigger pull as well.
Perhaps fitting in with Iron Man's research, it may not take much of a reduction in mass to solve any dropfire question.
Moon
 

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... a hammer exerts energy based upon the square of the hammer mass times its velocity divided by two ...
I usually find it difficult to evaluate comments like this, because most of us use common terms that we assume mean the same thing to different people, even though they sometimes do not. For example, the phrase "exerts energy" is seldom if ever seen in the standard literature. A body may have energy of a certain type, depending upon its position, speed, or some other measure. Further, a body may transfer energy in various ways. However most usually in physics, force rather than energy is "exerted."

In the present example, I assume you are referring to the kinetic energy of the hammer. If so, you state that the kinetic energy can be calculated as:

E = [(m) x (m) x (v)]/2

where m is the hammer mass and v is the hammer velocity. However in standard mechanics, the actual formula is:

E = [(m) x (v) x (v)]/2

which is quite different from what you wrote. Note also that this formula is specific for non-rotating objects, and since the hammer is constrained to rotation about it own fulcrum, we are actually dealing with an entirely different case.

Was this a typo?
 

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I actually experienced an accidental discharge... My PPK/s fired once during a jam. Broken spring in the magazine caused two shells to lodge in the slide/chamber, when I dropped the magazine the slide went to battery, causing the hammer to drop and discharged the round in the barrel. No one hurt, I was outside on my farm but still a little un-nerving. I will say, I was a little leary of carrying the Walther again until I ran it thru several test and was never able to replicate the same problem again. I now only use Walther magazines, springs and round nose ammo, no hollow points......
 

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Discussion Starter #20 (Edited)
Some 40 years ago, the H.P. White Laboratory performed some testing of the Walther PP-series safety system. The possibility of firing upward if the pistol were dropped --with the safety off-- so that it landed simultaneously on its hammer and rear tang had already been demonstrated with a PPK/s in perfect working condition. It did require a drop from fairly high --eye level, let's say, onto a pretty hard surface such as concrete. H.P. White also found that the height and surface hardness preconditions were progressively reduced as the strength of the firing pin spring was reduced. This was hardly surprising as the gun has an inertial firing pin.

But H.P. White also found a new wrinkle. If the pistol were not in perfect working condition- -for example, if the hammer rebound did not positively reset-- the hammer block would not re-engage to prevent firing if the hammer received a much lesser impact. A chronic or intermittent sticking of the hammer rebound can be caused many ways, some obvious and some less so. One common cause is a bent, worn or improperly adjusted mainspring strut. Even if the hammer rebound works, the hammer block may not, with the same result. A burr on or deformation of the hammer block or its bore in the frame, or just dirt impeding its free movement can defeat the rebound function. Also the very tiny (and often misidentified) sear spring may be broken, bent, incorrect, lame or missing altogether.

Any failure of rebound function leaves the hammer free to move forward and transmit to the firing pin any external impact it receives.

Which raises a question: How many of you who carry with the safety off periodically check the rebound function on your PP series pistols? This also applies to P.38s, which work similarly.

While the manual safety is on, there is no danger from a failure of hammer rebound. The safety doesn't care whether the rebound is functioning correctly or not. It both locks and shields the firing pin until the shooter flicks it off.

M
 
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