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Detail on CGW extended firing pins....


MoRivera
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In light of the recent accidental USPSA tragedy, there's understandably been a lot of talk regarding extended firing pins in CZ's.  I figured it'd be a good time to recall discussions and analyses done here and on other forums about them, and perhaps address some misconceptions.

 

Here's one from CZ-Forum....

 

https://czfirearms.us/index.php?topic=74890.0

 

 

And another from Enos.....

 

 

 

As you can see here, the 'extension' isn't the actual pin end, it's the rear striking section that extends back out of the slide where the hammer hits....  A Tactical Sport and stock Shadow, with the extended on the bottom. 

 

image.thumb.png.da3d3494fa1ddcc4bb87c439c4da4344.png

 

 

FPs.thumb.jpg.ca2cff568486d6313d956e1c6d0a850c.jpg

 

 

 

The difference in overall length between the two is

 

Stock: 2.466 inches

 

Extended: 2.503 inches

 

Difference of 0.037 inches...and again, that's in the rear portion.

 

 

My digital scale only goes down to 0.X ounces and single grams, so I can't tell the difference in weight in grains or the like, but it looks to be quite negligible when it comes to inertia from a 3 to 6 foot drop on the muzzle from rest.  So in that respect, considering such a minuscule difference in mass/inertia from stock, and NOT factoring a lighter firing pin spring, it does not seem that a CZ with this extended firing pin would be any more susceptible to a drop-fire on the muzzle than with a stock pin*.

 

As far as a drop on the hammer, as has been reported to be the case in the aforementioned mishap.....yes at rest with the hammer fully down and pressing against the rear of the pin until it's flush with the rear slide surface, the extended pin is 0.037 inches closer to a loaded primer than stock.  But as has been brought up in other posts pertaining to the aforementioned tragedy...what would make the pin move forward from an impact on the hammer if the hammer is already resting on the frame?  Maybe just the transfer of shock?  Or maybe in the aforementioned incident, the floor might have impacted the rear tang/beavertail for an instant before the gun rotated a tiny bit to impact the hammer, and that was just enough to move the hammer back a tiny amount before it was moved forward by the hammer impact?

 

(* So with the hammer at fully-forward rest, the firing pin has 0.037 inches less to travel on a muzzle-down drop.  But again, that's very small and we're talking a teeny-weeny difference in mass/inertia.)

 

Or...as has been brought up, perhaps the competitor actually tried to catch the falling firearm and grabbed the trigger, and that detail hasn't been reported yet (but that's purely speculative/hypothetical from another related conversation, and not meant to allude here).  Whatever those details may be, maybe this will help us get a better grasp on how safe or more dangerous an extended firing pin is, and/or what other factors combined with it it (like a lighter firing pin spring) may or may not have contributed.

 

*ETA: TO CLARIFY, EXISTING REPORT IS THAT THE GUN FELL DOWN ON ITS HAMMER.  IN NO WAY IS IT BEING SUGGESTED THAT SAID REPORT IS FALSE OR THAT SOMETHING IS BEING COVERED UP.  SHOULDN'T NEED TO BE SAID, BUT APPARENTLY IT DOES SO JUST IGNORE THAT LAST PART.

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1 hour ago, MoRivera said:

In light of the recent accidental USPSA tragedy, there's understandably been a lot of talk regarding extended firing pins in CZ's.  I figured it'd be a good time to recall discussions and analyses done here and on other forums about them, and perhaps address some misconceptions.

 

Here's one from CZ-Forum....

 

https://czfirearms.us/index.php?topic=74890.0

 

 

And another from Enos.....

 

 

 

As you can see here, the 'extension' isn't the actual pin end, it's the rear striking section that extends back out of the slide where the hammer hits....  A Tactical Sport and stock Shadow, with the extended on the bottom. 

 

image.thumb.png.da3d3494fa1ddcc4bb87c439c4da4344.png

 

 

FPs.thumb.jpg.ca2cff568486d6313d956e1c6d0a850c.jpg

 

 

 

The difference in overall length between the two is

 

Stock: 2.466 inches

 

Extended: 2.503 inches

 

Difference of 0.037 inches...and again, that's in the rear portion.

 

 

My digital scale only goes down to 0.X ounces and single grams, so I can't tell the difference in weight in grains or the like, but it looks to be quite negligible when it comes to inertia from a 3 to 6 foot drop on the muzzle from rest.  So in that respect, considering such a minuscule difference in mass/inertia from stock, and NOT factoring a lighter firing pin spring, it does not seem that a CZ with this extended firing pin would be any more susceptible to a drop-fire on the muzzle than with a stock pin*.

 

As far as a drop on the hammer.....yes at rest with the hammer fully down and pressing against the rear of the pin until it's flush with the rear slide surface, the extended pin is 0.037 inches closer to a loaded primer than stock.  But as has been brought up in other posts pertaining to the aforementioned tragedy...what would make the pin move forward from an impact on the hammer if the hammer is already resting on the frame?  Maybe just the transfer of shock?  Or maybe in the aforementioned incident, the floor might have impacted the rear tang/beavertail for an instant before the gun rotated a tiny bit to impact the hammer, and that was just enough to move the hammer back a tiny amount before it was moved forward by the hammer impact?

 

(* So with the hammer at fully-forward rest, the firing pin has 0.037 inches less to travel on a muzzle-down drop.  But again, that's very small and we're talking a teeny-weeny difference in mass/inertia.)

 

Or...as has been brought up, perhaps the competitor actually tried to catch the falling firearm and grabbed the trigger, and that detail hasn't been reported yet.  Whatever those details may be, maybe this will help us get a better grasp on how safe or more dangerous an extended firing pin is, and/or what other factors combined with it it (like a lighter firing pin spring) may or may not have contributed.

How many times do you have to read that the gun fell on its hammer to set it  off?

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6 minutes ago, Sarge said:

How many times do you have to read that the gun fell on its hammer to set it  off?

That's not the point...that's been both clarified and mentioned by me several times in multiple posts...perhaps you should read that yourself.

 

Look before you p*ss, just some friendly advice.

 

This is simply a recall on extended firing pin details and info that address this incident as well as other general misgivings about them that have recently arisen...as I said in THE VERY FIRST SENTENCE.

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3 minutes ago, MoRivera said:

That's not the point...that's been both clarified and mentioned by me several times in multiple posts...perhaps you should read that yourself.

 

Look before you p*ss, just some friendly advice.

 

This is simply a recall on extended firing pin details and info that address this incident as well as other general misgivings about them that have recently arisen...as I said in THE VERY FIRST SENTENCE.

Then why say perhaps the shooter tried to grab It and hit the trigger? That’s all I’m asking. That is unsafe with any gun.

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33 minutes ago, Sarge said:

Then why say perhaps the shooter tried to grab It and hit the trigger? That’s all I’m asking. That is unsafe with any gun.

No , you may have meant that, but what you said was this.....

 

45 minutes ago, Sarge said:

How many times do you have to read that the gun fell on its hammer to set it  off?

 

Which is uncalled for.

 

It was purely speculative and hypothetical, it doesn't mean it's likely or that the existing report of a straight hammer drop isn't the actual truth.  That was brought up in another conversation regarding the fact that the hammer rests against the rear of the slide when fully forward, it's not meant to misinform.

 

Jesus Christ, man.

 

I added some further clarification, if that eases your mind.

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1 hour ago, MoRivera said:

what would make the pin move forward from an impact on the hammer if the hammer is already resting on the frame?  Maybe just the transfer of shock?  Or maybe in the aforementioned incident, the floor might have impacted the rear tang/beavertail for an instant before the gun rotated a tiny bit to impact the hammer, and that was just enough to move the hammer back a tiny amount before it was moved forward by the hammer impact?

 

 

 

Have you ever seen one of those newton's cradle things sitting on someone's desk? You know like 5 hanging metal balls with just the two end ones bouncing back and forth. The energy from one transfers through the center to the one on the other end and sends the last one flying up only to come back down and repeat the process in the other direction

 

Wouldn't this work the same way with the pin pressed against the hammer by the FP spring, then the hammer is impacted the slide can't move forward so where does the energy go? My guess into the pin, unless the spring is to much for that force to over come.  

 

I think saying "maybe he dropped the gun and tried to catch it" even though there are no reports that was what happened is just muddying the water for no reason. 

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14 minutes ago, Racinready300ex said:

 

Have you ever seen one of those newton's cradle things sitting on someone's desk? You know like 5 hanging metal balls with just the two end ones bouncing back and forth. The energy from one transfers through the center to the one on the other end and sends the last one flying up only to come back down and repeat the process in the other direction

 

Wouldn't this work the same way with the pin pressed against the hammer by the FP spring, then the hammer is impacted the slide can't move forward so where does the energy go? My guess into the pin, unless the spring is to much for that force to over come.  

 

I think saying "maybe he dropped the gun and tried to catch it" even though there are no reports that was what happened is just muddying the water for no reason. 

That's a very good example, I never thought of that.  Yeah can totally see that.

 

nLdaYxb.gif.276ae276fcf4200e99588d60bf6c4a26.gif

 

The only thing about that is in this case the firing pin itself already has kinetic energy in the opposite direction since it's falling....as opposed to being completely at rest with no movement or existing inertia like the ball bearings on the ends when they're launched outwards.  But then considering the mass of the gun and the floor hitting the hammer, maybe it overcomes the small amount of inertia from such a low mass like the pin.   I guess someone well versed in physics would know.

 

And yeah, it wasn't meant to mislead it was something brought up in another conversation, I tried to clarify that, just ignore that part.  Agreed, don't want to add more complication, this is about the firing pin and hammer.

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2 minutes ago, yigal said:

A few years ago I asked some club members to remove extended pins  only from cz guns  and use the original, because it is the best.

I'm thinking it's more abut the reduced firing pin spring more than the extended pin itself.

 

Has it been clarified in the reports that the competitor's gun had both the extended pin and reduced spring, as opposed to stock?

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5 minutes ago, MoRivera said:

I'm thinking it's more abut the reduced firing pin spring more than the extended pin itself.

 

Has it been clarified in the reports that the competitor's gun had both the extended pin and reduced spring, as opposed to stock?

 

I've herd the reduced springs can wear or even break fairly quickly. I wonder if one in good condition would have the problem. It'd be fairly easy to test different combinations. Just smack your hammer with a hammer and see if it goes off. Use a case with just a primer. 

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8 minutes ago, Racinready300ex said:

 

I've herd the reduced springs can wear or even break fairly quickly. I wonder if one in good condition would have the problem. It'd be fairly easy to test different combinations. Just smack your hammer with a hammer and see if it goes off. Use a case with just a primer. 

About a year and a half ago, a reduced-power spring I got from CGW was wearing out pretty early (like within three weeks), and what was happening was that the firing pin wasn't resetting all the way back...just kind of floating loosely in the firing pin channel.  Because of that some rounds weren't going off and when I ejected and looked at them, they had no marks on the primers.

 

It turns out I wasn't the only one and apparently CGW had gotten a bad batch of them...me being one of the unlucky who ordered at the time.  they sent me replacements which have been fine since over thousands of rounds.  Luckily I never dropped the gun during that time, but that's just an example...seemingly due to bad metallurgy moreso than 'early wear', if you will.

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7 minutes ago, MoRivera said:

About a year and a half ago, a reduced-power spring I got from CGW was wearing out pretty early (like within three weeks), and what was happening was that the firing pin wasn't resetting all the way back...just kind of floating loosely in the firing pin channel.  Because of that some rounds weren't going off and when I ejected and looked at them, they had no marks on the primers.

 

It turns out I wasn't the only one and apparently CGW had gotten a bad batch of them...me being one of the unlucky who ordered at the time.  they sent me replacements which have been fine since over thousands of rounds.  Luckily I never dropped the gun during that time, but that's just an example...seemingly due to bad metallurgy moreso than 'early wear', if you will.

 

That could be where that rumor comes from. Funny how one bad batch can give a product a bad rap in our small community. I just switched to CZ and have their spring and pin in my gun. I've been checking it just by pushing it in with my finger and going by feel. Still seems good after about a month of dry fire. Maybe 1500 rounds of live fire. 

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41 minutes ago, Racinready300ex said:

Have you ever seen one of those newton's cradle things sitting on someone's desk? [...] Wouldn't this work the same way with the pin pressed against the hammer by the FP spring

For that to happen, the firing pin spring (that pushes the firing pin and therefore the hammer back) needs to be stronger than the mainspring that pushes the hammer forward. Otherwise the hammer would rest on the firing pin stop, pushing it forward against the slide, and therefore not be able to push the firing pin forward relative to the slide when contacting the ground.

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I just replaced the reduced-power spring on the extended firing pin in my CZ Shadow with a regular power one.  11.5-lb hammer spring.  Compared the 'pencil test' to other guns.  You can definitelty feel the difference in the two springs just getting the rear pin-retainer back into the slide.

 

Left: reduced-power.  Right: stock.

 

IMG_2238.thumb.JPG.c6f79b31fd43cedcdbefda54f2224a61.JPG

 

With other guns such as Sigs and a CZ compact with stock springs and pins, the pencil moves out a bit by a few inches when the happen falls.  With the Shadow the pencil comes clearly out of the barrel....it would hit the low ceiling in my basement before, not this time but considerable more than the other mentioned pistols, all of which have no ignition problems with CCI Blazer Brass.  So I think the Shadow will be just fine with the normal-power firing pin spring and would probably be more than fine with the normal firing pin as well...but I at least think it's a bit safer from drop fire with the stronger firing pin spring than the reduced one.

 

I probably went overboard with the reduced power spring, as I'm not running an 8-lb hammer spring for a super-light double-action like some.  the 11.5-lb is as low as I want to go, double-action is smooth and light, but not crazy 5-lb light.

 

ETA: now the the stock firing pin spring is in, when the hammer is fully-forward, the rear of the pin does actually keep it a tiny bit off the rear slide surface. as opposed to the hammer being fully against etc rear surface with the reduced-power spring.  So I don't know if THIS is actually more susceptible to drop-dire on hammer since, as someone put in another thread, it would now have a slight 'running start' if struck.

 

KVID2237-2b.gif.190545457fc74ebcdcef913d201dbf99.gif

 

But I also have to think that the extra power keeping it pressed to the rear is the the main thing that keeps it from going forward too far....a few guys have recounted tests hitting a full-dropped hammer son their CZ's with a mallet, and it looks like the ones with reduced-power pin springs are the sones that set off the primered case.

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25 minutes ago, lstange said:

For that to happen, the firing pin spring (that pushes the firing pin and therefore the hammer back) needs to be stronger than the mainspring that pushes the hammer forward. Otherwise the hammer would rest on the firing pin stop, pushing it forward against the slide, and therefore not be able to push the firing pin forward relative to the slide when contacting the ground.

Not necessarily, if it's at rest against the hammer even though it's flush with the rear of the slide where the hammer is resting.  Like those middle bearings that are at rest, the vibration is sent right through them to the outermost one that has less or nothing holding it down.  In this case, the hammer being like those bearings in the middle, the floor being the bearing that hits one end, the firing pin being the bearing that's propelled outwards on the other end.

 

Theoretically at least.  We've got some guys here who have induced ignitions on chambered primer-only casings by hitting the rear of their CZ hammers with a mallet when they're fully forward.  Seems t one the same thing.

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27 minutes ago, lstange said:

For that to happen, the firing pin spring (that pushes the firing pin and therefore the hammer back) needs to be stronger than the mainspring that pushes the hammer forward. Otherwise the hammer would rest on the firing pin stop, pushing it forward against the slide, and therefore not be able to push the firing pin forward relative to the slide when contacting the ground.

 

I'm saying the pin is in contact with the hammer. When the energy hits the hammer it will transfer into the pin too, not just the slide. The hammer is pressing against both the pin and the stop, not just the slide. The slide can't move forward but the pin can. 

 

If you're correct then hitting the hammer with it fully down couldn't set off the round. But, someone posted in the other thread testing this by hitting the hammer with a hammer and it set the round off in the chamber. 

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19 minutes ago, MoRivera said:

Like those middle bearings that are at rest

The middle bearings are actually not at rest. Each one of them moves a little bit when hit, but the distance is small and it happens too fast for us to see.

 

Imagine a hammer with a flat surface instead of the first bearing, and two large metal blocks to the left and to the right of the rest of the bearing stack, arranged so that they are flush with the second bearing. When you hit that contraption with the flat hammer, first bearing and both large metal blocks will move forward with the same speed.

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9 minutes ago, lstange said:

The middle bearings are actually not at rest. Each one of them moves a little bit when hit, but the distance is small and it happens too fast for us to see.

 

Imagine a hammer with a flat surface instead of the first bearing, and two large metal blocks to the left and to the right of the rest of the bearing stack, arranged so that they are flush with the second bearing. When you hit that contraption with the flat hammer, first bearing and both large metal blocks will move forward with the same speed.

But by that reckoning, the frame and resting hammer could be moving at least a bit just from bouncing off the hard concrete, no?

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17 minutes ago, Racinready300ex said:

The hammer is pressing against both the pin and the stop, not just the slide. The slide can't move forward but the pin can.

For the firing pin to move forward relative to the slide, the front surface of the hammer that is in contact with the firing pin needs to move forward relative to the slide. This can happen if a) the firing pin stop moves forward relative to the slide when hit by the hammer, even by just a little, or b) the hammer is not in contact with the firing pin stop initially, and the firing pin is protruding back from the hole in the firing pin stop.

 

If the rear surface of the firing pin is initially flush with the rear surface of the firing pin stop, and the firing pin stop is all the way forward in its slot inside the frame, I don't see a way how the hammer can accelerate the firing pin more than the slide.

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2 minutes ago, MoRivera said:

But by that reckoning, the frame and resting hammer could be moving at least a bit just from bouncing off the hard concrete, no?

Yes they could. But for the gun to fire, the firing pin needs to move relative to the slide. The hammer needs to accelerate the firing pin differently compared to the slide.

 

The difference in weight is not enough. If you put an empty can and a full can on a tray, then raise the tray up quickly, it's not like the empty can will fly higher.

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6 minutes ago, lstange said:

Yes they could. But for the gun to fire, the firing pin needs to move relative to the slide. The hammer needs to accelerate the firing pin differently compared to the slide.

 

The difference in weight is not enough. If you put an empty can and a full can on a tray, then raise the tray up quickly, it's not like the empty can will fly higher.

That's why I look at those ball bearings as an example as to how it could happen.  And in your example, the empty can will fly higher if the full one is glued to the tray.  A slide cannot move forward off the frame because it is fully forward and locked/anchored in as is the hammer, but the pin inside is more free-floating in comparison.  So much like the bearings, the hammer and slide are the middle bearings held relatively still by their mass and the mass in front of them, and the firing pin is like the bearing on the other end which has nothing holding it back.  At least that's how I see it.  Also....

 

3 hours ago, je85 said:

This was unfortunately the perfect storm.

 

I did some non scientific testing. 

Shadow 2 11lb hammer spring

Federal match primers.

I used a heavy rubber mallet.

 

1. extended fp and worn out light fp spring.

1.1 Hammer down hitting beaver tail,

Nothing.

1.2 hammer cocked Safety off hitting beaver tail, nothing

1.3 hammer down hitting hammer, bingo ignition.

 

2. Factory fp and factory spring, above testing done in same manner with no ignition.

 

3. Extended fp factory spring

Above testing done in same manner with no ignition

 

Note all above testing was to me equivalent to throwing the gun on a very hard surface not dropping it.

I have not done simulated testing for gun dropping on muzzle.

 

Jumping to conclusions on this accident is not smart. Are we all Democrats now? We need the actual facts. 

 

Even before this incident I felt we needed a better platform for training new shooters before shooting a match.

 

If you don't feel safe going to a match after this incident than go find a different hobby, we don't need you in the sport. Sorry not sorry.

 

My thoughts and prayers go out to both families. 

 

 

 

 

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6 minutes ago, lstange said:

For the firing pin to move forward relative to the slide, the front surface of the hammer that is in contact with the firing pin needs to move forward relative to the slide. This can happen if a) the firing pin stop moves forward relative to the slide when hit by the hammer, even by just a little, or b) the hammer is not in contact with the firing pin stop initially, and the firing pin is protruding back from the hole in the firing pin stop.

 

If the rear surface of the firing pin is initially flush with the rear surface of the firing pin stop, and the firing pin stop is all the way forward in its slot inside the frame, I don't see a way how the hammer can accelerate the firing pin more than the slide.

 

Think about it like this, if I drop the pin on concrete will it bounce? This is a floating pin inside of a 4 lbs weight being dropped 3' onto concrete that only needs to move a few thousands up to contact the primer. 

 

So in this case what would you guess caused the shooters gun to go off when it hit the floor? And what about the guy in the other thread said he hit his hammer with a hammer with a extended pin and worn out lightened spring it ignited the primer what would of caused that?

 

Certainly plenty of contradictory theories as to how this could happen, which is a good reason not to jump into rule changes as some are suggesting. 

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