Let's talk about 1st, 2nd, 3rd gen firing pins

[JohnHL]

A few days ago, member audiec01 posted the following question:

As I have been reading and looking for parts, I have seen references to multiple shank sizes for firing pins:


Firing Pin (.540" Center Shank, overall 2.205")
Firing Pin (.530" Center Shank, overall 2.205")
Firing Pin (.390" Center Shank, overall 2.205")
Firing Pin (.385" Center Shank, overall 2.205")
Firing Pin (.300" Center Shank, overall 2.205")


So now I have questions to what is the reason for all these different Shank sizes... and furthermore, what part of the firing do you measure to determine the shank size.

I wanted to answer the question, but because I've never encountered a failed or damaged firing pin in a 1st, 2nd, or 3rd gen pistol, I hadn't taken the time to study them.

I've cleaned my share of gunked-up firing pin tunnels, but the pins were fine.

I recalled a question here on the Forum posted by member kbm6893 in which he asked:

Looking to pick up a few. Numrich lists the same part of the 3913,3953,3953TSW, 6946, 5946, and 5906. Part number 923810, .530” long. They all take the same firing pin?

To which armorer951 correctly responded (as usual):

Smith and Wesson's part number is 10636. (and, 27313)

(I believe the number you referred to is a Numrich number)

Yes, the model numbers you list above appear to use the same firing pin. The measurement they refer to, .530", is the "center shank" of the firing pin. This center shank is a different length for the 2nd and 3rd gen models.....2nd gen shank is approx. .390" in length, and, consequently, they (the 2nd/3rd gen) use different length firing pin springs.


If you need parts information, PDF's of the parts lists are here on the forum:

PDF's of the Parts Lists

Carter

Again, an excellent response, but I wanted to dig a little deeper.

I started with the S&W parts lists and learned that S&W settled on two firing pins for 1st, 2nd, and 3rd gens:

273130000 for the 9mm (single and double stacks) and 40s&w (double stacks)

067670000 for the .45, 10mm, and 40s&w (single stacks)

That still didn't tell me much so I went to my stash of spares and pulled out the 17 firing pins and at least that many unattached slide assemblies and decided to give my dial calipers a workout.

Below is a typical picture of a firing pin that I borrowed from the web:

My measurements tell me the 9mm firing pin is 2.20" and the 45 firing pin is 2.31" long.

1st gen pins have a single annular groove at the rear to be captured by the manual safety body.

2nd and 3rd gen pins have a second annular groove to be captured by the firing pin safety plunger.

That thick area in the center is the "shank".
It is the major diameter of the pin (.240").

On the 45 firing pin the shank is .45" inches long. (easy to remember)

On the 9mm pin I've encountered shank lengths of .530", .390", and .300".

The .530" shank was first used on the 1st gen models with the single safety groove.

On 2nd gen models, S&W elected to go with the .390" shank with the double safety grooves.

They returned to the .530" shank with the double safety grooves on the 3rd gen (and final iteration) of that firing pin.

I have but one 2.20" firing pin pin with the .300" shank and double safety grooves and do not know to which models it was fitted, however when comparing it to the 1st gen (single safety groove) pin, it appears to have the same dimensions as the .530" single groove pin with the second groove added.

My guess is that it was too light (for an inertial pin) and may have resulted in misfires under less than optimal conditions when used with the 1st gen firing pin spring.

The .540" and .385" shank dimensions audiec01 encountered were probably the result of the difficulty in measuring actual shank length because neither end is square.

That's all I got.

I hope someone more knowledgeable than myself can come along and shed a little more light on firing pins.

John

 

[4T5GUY]

I went to my stash of spares and pulled out the 17 firing pins and at least that many unattached slide assemblies.

I thought I had “too many” !!! I’ve also never had to replace a 1st, 2nd or 3rd Gen firing pin. I had one shoot across the room and down the stairs once. Couldn’t find it, (I eventually did,) but had a spare so no problem. Just embarrassment.

Thanks for another simple, clear and understandable tutorial. Great info.

Jim

 

[JohnHL]

I thought I had “too many” !!! I’ve also never had to replace a 1st, 2nd or 3rd Gen firing pin. I had one shoot across the room and down the stairs once. Couldn’t find it, (I eventually did,) but had a spare so no problem. Just embarrassment.

Thanks for another simple, clear and understandable tutorial. Great info.

Jim

Thanks for the kind words, Jim!

A few spare parts here, a spare slide there, and before I knew it, I had a fairly good supply of parts.

But some of these parts, like firing pins, tend to look so much alike that I hadn't noticed the differences.

I did this this mostly for my own edification, but as others were curious about the same things, I figured I'd post my results, hoping they would help.

John

 

[armorer951]

Thanks John for that extra bit of work. It's a miracle we're still curious about such things, isn't it?

One takeaway to remember is that these pins are not interchangeable, so use caution.

Carter

 

[audiec01]

JohnHL, thank you very much for the research you put into this subject.
​

I have a complete and original 1982-459 with .300" Center Shank, overall, 2.20", dia. .240" with approximately a 1.26" long Spring.


I have a 659 Slide that was fitted with a .300" Center Shank, overall, 2.20", dia. .240" with approximately 1.26" long Spring.


I have a 659 Red Dot slide fitted with .390" Center Shank, overall, 2.20", dia. .240" with approximately 1.15” long Spring.


I purchased two 659 Firing Pins from Midway .390" Center Shank, overall 2.20", dia. .240" (shank was not identified in the seller site).


JackFirstInc has Firing Pins listed as .390" Center Shank, overall, 2.20", dia. .240" that fit the Models: 59, 459, 559.


JackFirstInc has Firing Pins listed as .385" Center Shank, overall, 2.20", dia. .240" that fit the Model: 659.


Numrich GPC has Firing Pins listed for the 459 with .530" Center Shank, overall, 2.20", dia. .240" that fit the Models: 39, 39-2, 459, 559, 59, 469, 669, 439, 539.


Numrich GPC has Firing Pins listed for the 559 with .530" Center Shank, overall, 2.20", dia. .240" that fit the Models: 39, 39-2, 459, 559, 59, 469, 669, 439, 539.


JackFirstInc has Firing Pins listed as .540" Center Shank, overall, 2.20", dia. .240" that fit the 59 Series Pistols.


Wolff Extra Power (EP) Spring approximately 1.15” long for Models: 39, 439, 539, 639, 3904, 3906, 3913, 3914, 3944, 3946, 3953, 3954, 59, 459, 559, 659, 5903, 5904, 5906, 5923, 5924, 5926, 5943, 5944, 5946, 5967, 469, 669, 6904,6906, 6924,6926, 6944, 6946, 410, 411, 4003, 4004, 4006,4026,4043,4044, 4046, 910, 915


This is what prompted my post about Firing Pins, what is most concerning to me was the lack of information for Spring length. Wolff only sells the Extra Power Spring for the above Models regardless of the Shank Size. If you install a Firing Pin with to short or to long of a Spring, I don’t see how you would get proper primer strikes.


Audie

 

[4T5GUY]

This is what prompted my post about Firing Pins, what is most concerning to me was the lack of information for Spring length. ​

Well “Times New Roman Pink” is different and new for me. That’s cool, no issues here. I’m glad I didn’t respond right away as JohnHL and armorer951 thankfully did.

I initially thought you were asking about FP’s NOT FP SPRINGS. Guess I missed it. I’ve replaced FP springs w/factory S&W and Wolf that were example specific and they always were functionally perfect. That is including XPower from Wolf. I’m not a factory trained armorer so I really shouldn’t with validity even be commenting.

The initial post got me interested though so thanks for that. I learned a bunch.

Jim​

 

[audiec01]

Well “Times New Roman Pink” is different and new for me. That’s cool, no issues here. I’m glad I didn’t respond right away as JohnHL and armorer951 thankfully did.

I initially thought you were asking about FP’s NOT FP SPRINGS. Guess I missed it. I’ve replaced FP springs w/factory S&W and Wolf that were example specific and they always were functionally perfect. That is including XPower from Wolf. I’m not a factory trained armorer so I really shouldn’t with validity even be commenting.

The initial post got me interested though so thanks for that. I learned a bunch.

Jim

Jim, To me, the Firing Pin and Firing Pin Spring go hand in hand... by the way, I have color vision problems...



Audie

 

[JohnHL]

Thanks John for that extra bit of work. It's a miracle we're still curious about such things, isn't it?

One takeaway to remember is that these pins are not interchangeable, so use caution.

Carter

You're most welcome, Carter!

And Thank You for being so selfless and generous with your time, knowledge, and experience here on the Forum.

Whenever you respond to a post, I always take the time to read your words of wisdom, even if the subject matter is not top of mind to me.

Your revolver chops are fantastic!

Your choice of the word "miracle" to describe our innate curiosity struck a chord with me.
With each passing year, many of the things I once took for granted have been revealed to me as having a greater percentage of "divine inspiration".

I take your advice that the firing pins are varied and not interchangeable, but it would seem that the latest 9mm firing pin (.540" center shank/double safety groove) and its associated spring (106370000) seem to be "backward compatible" with earlier models.

Here's to all the members of this Forum who find the insides of machines to be more fascinating than the outsides!

John

 

[JohnHL]

JohnHL, thank you very much for the research you put into this subject.
​

I have a complete and original 1982-459 with .300" Center Shank, overall, 2.20", dia. .240" with approximately a 1.26" long Spring.


I have a 659 Slide that was fitted with a .300" Center Shank, overall, 2.20", dia. .240" with approximately 1.26" long Spring.


I have a 659 Red Dot slide fitted with .390" Center Shank, overall, 2.20", dia. .240" with approximately 1.15” long Spring.


I purchased two 659 Firing Pins from Midway .390" Center Shank, overall 2.20", dia. .240" (shank was not identified in the seller site).


JackFirstInc has Firing Pins listed as .390" Center Shank, overall, 2.20", dia. .240" that fit the Models: 59, 459, 559.


JackFirstInc has Firing Pins listed as .385" Center Shank, overall, 2.20", dia. .240" that fit the Model: 659.


Numrich GPC has Firing Pins listed for the 459 with .530" Center Shank, overall, 2.20", dia. .240" that fit the Models: 39, 39-2, 459, 559, 59, 469, 669, 439, 539.


Numrich GPC has Firing Pins listed for the 559 with .530" Center Shank, overall, 2.20", dia. .240" that fit the Models: 39, 39-2, 459, 559, 59, 469, 669, 439, 539.


JackFirstInc has Firing Pins listed as .540" Center Shank, overall, 2.20", dia. .240" that fit the 59 Series Pistols.


Wolff Extra Power (EP) Spring approximately 1.15” long for Models: 39, 439, 539, 639, 3904, 3906, 3913, 3914, 3944, 3946, 3953, 3954, 59, 459, 559, 659, 5903, 5904, 5906, 5923, 5924, 5926, 5943, 5944, 5946, 5967, 469, 669, 6904,6906, 6924,6926, 6944, 6946, 410, 411, 4003, 4004, 4006,4026,4043,4044, 4046, 910, 915


This is what prompted my post about Firing Pins, what is most concerning to me was the lack of information for Spring length. Wolff only sells the Extra Power Spring for the above Models regardless of the Shank Size. If you install a Firing Pin with to short or to long of a Spring, I don’t see how you would get proper primer strikes.


Audie

Hi, Audie!

You're very welcome and Thank You for taking the time to make measurements and document them.

I didn't pull apart my old "used but not abused" early model 439 (my oldest S&W semi-auto) but you seemed to have confirmed my suspicions that the .300" shank length pin was the immediate successor to the 1st gen pin.

I completely agree that the FP and its spring go hand in hand and the spring would seem to need to be matched to the pin.

I checked a couple of springs I have and got measurements of 1.30" for an early spring and 1.03" for a late spring.

I don't think I have any Wolff FP springs, but your listed length of 1.15" is about in the middle, so maybe they are correct that theirs is the universal length and will fit everything from a 39 no-dash to a 4046TSW!

Speaking of springs, I don't think I've ever replaced a FP spring.

As long as the spring retracts the pin all the way back yet allows it to protrude through the breach face, it is doing all the job it needs to do.

Some folks subscribe to the philosophy that if replacing some springs is good, then replacing all springs must be better.

There is reason to replace recoil springs (too weak and a frame could crack).

There is reason to replace magazine springs (too weak and failures to function can occur).

But as long as all the other springs are present and unbroken, I've witnessed no signs of fatigue and leave them as they are.

I hope this can shed a little more light on your questions.

John

 

[Model 10-8]

Thank goodness for smart people. Great thread.