Unsafe for carry?

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Handy

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It has been strenuously stated in this thread:

http://www.thehighroad.org/showthread.php?s=&threadid=13300

and others that inertial firing pins do not offer the shooter any protection against dropping the gun on the hammer (hammer down carry). But it has always been my understanding that was the only reason for the inertial firing pin to exist.

The following pistols have often been carried hammer down on a loaded chamber, no automatic pin block (cond. 2). Has anyone ever heard of an AD caused by a blow to the hammer in these or any similar guns?

CZ-75A
Earlier Witness, AT84, TZ75
Baby Eagle decocker
Desert Eagle
Beretta 92S and earlier, including clones
Beretta 21 and 950
Beretta 1934
Beretta 84, 85 and Browning BDA
Earlier Browning HighPower and clones
Walther PP, PPK
Walther TPH
Mauser C96 Broomhandle
Mauser HSc
S&W 39 and 59
Bersa .380 and Firestorm
Colt 1911 series 70 and similar
Colt/Astra Cub
Mab PA-15
VIS Radom
Star B and BM
Steyr 1912

Those are the ones in my disassembly book that have hammers that rest against an inertial firing pin for carry. There are certainly more than that.

I would really appreciate any information that alludes to the dangerous nature of these firearms in cond. 2 from hammer strikes. Muzzle strikes are a seperate problem, unrelated to the hammer. Thanks.
 
Hello. I cannot say what might happen nor argue either side, but I will relate what I did do and did observe.

Several years ago, I had an old Colt 1911 that I was changing out the sear and hammer in. I'd already determined that this 1911 would pop a cap from half-cock (used primed, empty cases) when I decided to see what might happen if the hammer took a blow.

Put a primed case in the bbl and lowered the hammer to full rest against the firing pin and retaining plate. With the gun's muzzle resting against my workbench top in a vertical position, I smacked the rear of the hammer 10 times just as hard as I could with a plastic mallet.

The primer was not detonated nor did it appear to've been hit even lightly by the pin.

Maybe I didn't hit it hard enough; I don't know, but it was darned hard as I could swing it. The muzzle of the bbl made some slight indentions in the wood surface. Maybe that cushioned it too much? I doubt it but don't know.

None of my 1911s have internal firing pin safeties. I prefer it that way, but I'd also say that the "sure" way is to go with one that does if this is a concern.

Best.
 
Intertial firing pins are just that, firing pins that only work when extreme interia is exhibited against them, enough so as to cause the firing pin to have enough force to strike the primer enough to cause it to discharge. Intertial firing pins DO NOT rest on the primer. As Mr. Camp demonstrated, they will not cause a discharge unless "properly motivated".

I'm so tired of the heresay and "I think I'll repeat what someone else said" on this forum that I'm starting to believe it is spreading as much disinformation as information.
 
Now Stephen... you know you should have used a chunk of concrete to bang on that hammer... it has unique properties that just can't be found in "plastic". :evil:
 
Comments on the inertial firing pin - - -

Inertia is (partially) defined as the tendency of an object to remain at rest. It takes some force to overcome inertia and make the object at rest LEAVE resting place and begin moving.

The firing pin rides in a channel a little longer than the pin itself. In condition 2, the pin is held rearward by its spring, in contact with the hammer face, away from the primer. With hammer at rest, no amount of pounding, smacking or impacting will cause the pin to go forward and set off the primer.

By design, the pin moves against the primer only when its inertia is overcome. That movement must have a certain amount of force to set off the primer. The force imparted by the falling hammer to the rear of the pin is sufficient to overcome pin inertia AND the rearward push of the spring. The pin flies forward, strikes the primer, etc.

Okay— The pin's inertia may be overcome in two other ways.
One: By imparting sufficient force to the FRONT of the slide (big mallet?) to move slide to the rear, allowing the pin to remain in place, and in effect driving the primer onto the stationary nose of the pin. This also stipulates that the pistol is free to move rearward, at least slightly, with the impact.

Two: If the pistol travels muzzle forward (okay, probably DOWNward,) the pin is moving at the same speed. Given sufficient velocity, the muzzle can strike a hard surface, halting the slide but allowing the pin to continues its forward travel. If it overcomes spring tension, the pin strikes the primer and the ignition occurs. I don't have enough knowledge of physics and the coefficients of friction to express this activity mathematically. I also don't know the weight of the pin or the tension of the firing pin spring. The relative smoothness of the pin shaft and interior of the channel have something to do with it. In any case, repeated experiments showed that the loaded pistol must drop from a certain height, at a certain weight, to attain enough velocity for all these circumstances to allow for discharge of the pistol. ALL conditions being met - - - Full 39-ounce service pistol, full load of ammo, axis of the bore exactly perpendicular to an exactly horizontal surface of seasoned concrete - - - discharge TYPICALLY takes place given a fall of some 17 feet. Yes, I've also read 20 feet, and also 27 feet. Seventeen is what I recall.

As anyone who has conducted any experimentation knows, if ANY condition is varied, the whole result may be skewed, by some factor large or small. What if there are only two rounds in the pistol? Suppose the muzzle strikes at 12.9 degrees off perpendicular. And, if the floor is hard wood instead of concrete? Any of these might require a longer fall.

Okay, all conditions are met and the pistol fires--Absolutely straight down. This can be awfully disconcerting, and COULD cause foot injury to someone standing nearby. Uncomfortable but hardly widespread carnage and disaster.

None of the above will change any aspect of the "controversy," but I'd like to clarify those points.

Best,
Johnny
 
The firing pin rides in a channel a little longer than the pin itself.
Click to expand...
You sure it's not the pin that's a little longer than the channel, Johnny?
 
Hello. No, he's correct. The firing pin channel is longer than the firing pin in an pistol having an inertial pin.

Best.
 
Stephen,

Probably should have, but didn't want to ruin the hammer!
Click to expand...

One must at times make sacrifices for science... I guess that's why we ain't scientists! :what:

Maybe that temperamental Commander you once owned would have been a better concrete candidate! :D
 
I'll just throw this up one more time so all have a chance to but 2 cents in.

This is a popular bit of gun folklore that inertial pins and hammers don't mix. So would ANYONE care to back that up?

Somebody here must have a friend's uncle's employee's mom who shot a hole in the ceiling when she dropped her (insert gun here) on the hammer!


Everybody knows about the danger of SAA revolvers and carrying one under hammer. I've seen some dramatic scars, personally. But if you want to repeat this other saw about inertial firing pins, now is a great time to back it up with a little anecdotal evidense.

Thanks!
 
Several years ago, my PPK fell out of my jacket pocket as I was exiting the car. The PPK is weighted so that, should it fall, it WILL land on its' hammer. The safety was on and, while I held my breath as it dropped, it landed squarely on its' hammer but nothing happened. Not sure if this story is the least bit helpful at all, just wanted to share my one episode of dropping a pistol. It tends to tighten up one's sphincter when you see it falling and the barrel is pointed your way.:what:
 
L.O.T.,

Thanks much. Technically, it's not a good example: the PPK safety is a firing pin block (albeit a manual, rather than automatic one). But it's generally nice to hear of an incident like that where everything worked as it should.

Glad you're in one piece.:)
 
An impact on the hammer cannot discharge the pistol - - -

- - -SO LONG AS THE HAMMER IS ALL THE WAY FORWARD.
If the hammer is set at "half cock," this is a different story. The "safety notch" is not and was never intended as a mode of carry. It was/is provided to catch the hammer is the full cock notch fails, or if someone's thumb slips while bringing the hammer from full forward to full cock.

If the hammer is left with the safety notch resting on the sear, then a heavy impact, or a fall directly onto the hammer, sufficient to break the sear or to shear off the notch, WILL allow the piece to fire. The fall of the hammer from the safety notch to the firing pin IS far enough to overcome the firing pin's inertia.

Again--carrying the pistol with hammer engaged on safety notch is NOT a 'Safe" condition. Far better to carry it at full cock, even WITHOUT thumb safety engaged on an unmodified pistol. The grip safety tang protects the fully-cocked hammer from an angular impact that could cause sear or hammer notch to fail.

(No, I do not carry 1911-types without thumb safety engaged. But it would be safer to do that than to carry at "Half Cock." I do NOT deactivate grip safety on my pistols. No use tempting fate.;) )

Best,
Johnny
 
That's an excellent point Johnny, and I always try to point out the same.

A little off topic:
In the case of pistols with firing pin safety blocks, like the CZ-75B, it has become some people's habit to carry at half cock. There is no safety issue in that case, but I would caution that if the gun is dropped on the hammer at halfcock, it's probably not going to fire again due to the sear damage. Full down is a little more impact resistant.
 
I like firing pin safeties if they were designed into the weapon from the beginning (i.e. Sig P series). I don't like them if they are add-ons to the weapon (i.e. 1911).

The only 1911 I've ever carried didn't have one, and I could have cared less.
 
Johnny Guest
Your explaination is excellant, thorough, and correct; except for one small detail. The term "inertia firing pin" refers to the fact that after the hammer strikes the firing pin, the "inertia" of the firing pin is what carrys it forward overcoming the force of the firing pin spring to fire the cartridge. This is what allows the firing pin to reach the primer even though the pin is shorter than the channel.
 
Matter of Balance

The weapon Can fire if you drop the pistol on it's muzzle onto a hard substains like concrete from high enough, or if your recoil spring is way too powerful for your firing pin spring.

White Labs did some test and found that with a factory firing pin spring, the 1911 would go off if dropped on Concrete from a little over 6 feet.

Other tests showed that the weapon would land on the muzzle about 1 out of 200 trys. So if you are real tall and really clumzy. You are likely to kill a sidewalk and should carry an 80s Series.

The reason Wolff sends extra power Firing Pin Springs with their Recoil Springs is so you change both. DO IT.
 
Raymond,

The muzzle drop thing varies from the 6' low you list to 20' and 27' feet, depending who you talk to. Of interest, California did a series of drop test that passed series 70 type guns from LesBaer and others. Who knows.
 
There are two interesting articles on 1911 muzzle drops here and here. They give measurements of things like firing pin weight, spring weight, and the amount of force required to detonate a primer.

There are probably way too many variables involved to get an exact figure of the height a 1911 needs to be dropped from to cause a discharge. Fooling around with calculations based on the measurements in the articles though, it seems that getting an AD from any reasonable height is very unlikely.
 
Lazhuward,

Those are just great. I think the "science" in the second article is a little shaky (static vs. dynamic tests), but it's hard to argue with actually dropping the slide from 15'.

Unfortunately, the hammer down drop is only briefly mentioned in the first article.

My thinking is that you have to take the energy needed for a muzzle drop, add to it the energy necessary to reverse the direction of the firing pins travel and the energy lost transmitting the impact vibration through the hammer into the pin.

I would think the energy needed for the hammer strike ignition, if even possible, would be at least twice that of the muzzle drop.
 
would think the energy needed for the hammer strike ignition, if even possible, would be at least twice that of the muzzle drop.
Click to expand...

Probably right. It CAN happen as with a muzzle drop, but highly unlikely. Not something I'd be concerned about, and why I believe the Schwartz and Series 80 safeties are very unnecessary.
 
I don't know about late production models, but the earlier Star Model B's had full length firing pins. While he doesn't care for the 9mm, Jeff Cooper sometimes recommended the Star BKS as a handy piece in that caliber, and noted that the long firing pin could be addressed by grinding a little off the tip. Jan Stevenson, in Guns Magazine, was a fan of the Star, and I believe he also noted the firing pin length.
 
Wouldn't a better name for this style pin be "freefloating"? As opposed to "captured"? So a Glock would be a captured pin, while a 1911 would be a freefloating pin.

And I don't think that a 1911 would fire from half cock. One of the Glock's safety features is that the gun is half-cocked, and only fully cocked when the tigger is fully depressed. So should all the safeties fail, the gun *still* won't go off. Going by that, I'd assume that a 1911 can't fire from half-cocked.

However, I haven't tried it. *I* could very well be half-cocked! :D
 
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