First off, I won’t go into why I found myself “messing with” my J Frame Firing Pins.
You can find that here if you are so inclined.

Apex J Frame Firing Pins

Using the S&W Parts & Accessory Catalog I found a number of different part no’s listed for J Frame Firing Pins and since I wasn’t entirely sure which ones I needed and they were relatively inexpensive (around $4 each) I ordered two different part no’s directly from S&W.

More than one J Frame Model listed 2, and sometimes 3, part no’s for Firing Pins (different –models) in the Parts & Acc. Catalog and I’ll use the common M642 to illustrate this.

M642

21044 Firing Pin

21507 Firing Pin MIM (OBS) Does OBS mean Obsolete?

22952 Firing Pin

04346 Firing Pin Spring (common to the different pins)

By cross referencing different models I chose to order the two non-MIM pins listed above.

Here’s what I found when measuring the Firing Pins (Pt. # 22952) that came stock in 3 of my guns.

M642-2 (one gun from 2008 & the other from ’09)
.484” (both pins the same length)

M638-3 (May 2011 & Jan 2012 guns)
.489” (both pins the same length)

New S&W pins, ordered from S&W Jan & Feb 2012, measurements below:

#22952 (12 measured) Current frame mounted pin
.492” (11 of the 12 measured)
.493” (12th pin)

#21044 (6 measured) Older style frame mounted pin
.493”-.494” (4 of the 6 measured)
.489” (remaining 2 pins)





I’ll be cleaning up the action on another M638-3 tonight or tomorrow night and should find a pin, based on the above, measuring .492” since the spent brass in the box is dated Jan 12, 2012. Edited to add: I was wrong, the pin on this gun was .489" and the information has been added above.

All 3 guns that I have already worked have had the most current pins installed (from those recently ordered) and the original firing pin springs left in them. All three also now have reduced power springs installed. In one of the 642’s I went with a Wilson Combat 8 lb mainspring & 14 lb rebound & in the other 642-2 I chose to use the Wolff 8lb mainspring & 15 lb rebound. The M638-3 also got Wolff Springs and in order to keep the single action pull weight up I chose the 15 lb rebound spring. On the M642’s I used different weight rebound springs because those weights felt right for that particular gun.

So far I only have approx. 125 rounds through each gun using Remington, Sellier & Bellot, Magtech and Fiocchi ammo with no light primer strikes. While test firing I visually checked the primer hits on the spent brass and am finding nice, deep, indentations from all 3 guns. More testing planned as soon as I dig out some other brands of ammo.

I only mention the reduced weight springs in the context of the firing pins since they play a vital role in what I’m doing. Actually I strongly discourage anyone who doesn’t fully understand how a revolver’s action works, and how friction affects its ability to function reliably, from installing reduced power springs, especially on a self defense gun. My main purpose isn’t to get a “light trigger” per se; it’s more about smoothness & balance.

With the actions polished & lighter springs installed I’m still looking at these weights, averaged over 25 trigger pulls using a Lyman Digital Gauge.

M642-2 w/Wilson 8lb MS / 14 lb RBS
10 lb. 15.0 oz.

M642-2 w/Wolff 8 lb MS / 15 lb RBS
10 lb. 15.5 oz.

M638-3 w/Wolff 8 lb MS / 15 lb RBS
10 lb. 11.5 oz.

M638-3 w/Wolff 8 lb MS / 15 lb RBS
10 lb. 14.0 oz

I could easily get those weights down with lighter rebound springs but would then run the risk of sluggish trigger re-sets.

One other thing I learned, the J Frames are a different critter than the K/L & N Frames, which have a larger hammer (K/L & N) so get the benefit of more inertia when hitting the firing pin due to the hammer’s longer arc of travel. This is why J Frames can be a little more problematic when using lighter weight springs. Notice I said, can be.

P.S. For the record, I am not a Gunsmith, just a regular Joe passing along some of the things he’s learned over the last couple of months.

P.P.S. Before I started working on my revolvers I spent months collecting all of the reference material I could get my hands on to learn all I could on the subject.
If I had to recommend just one it would have to be, Jerry Miculek's "Trigger Job" DVD.

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Ogy

As far as I know it boils down to 2 frame mounted firing pins in J frames. The "old style" firing pins for the guns with the external firing pin cross pin (retaining pin) and the "new style" firing pin common to all the MIM centerfire guns. I believe all the older part #'s supercede into the latest part # for each type. What pin you actually get will depend on where you order it from and how current their stock is and what S&W is currently making. There have been a number of different length and tip shape "new style" pins, apparently starting with the first version that was a steel hemispherical tipped pin ~ .495.

FWIW, in the "new style" MIM guns I use the S&W hemispherical tip pins that measure .492+, preferably .495 but I have and have had good results with .492 pins.

My current carry gun, a (no lock) 342, fires CCI primers reliabley with a 7 lb 4 oz DA pull (with a crisp trigger return) measured with a Lyman digital gauge. It has a S&W .495, titanium, hemispherical tipped firing pin. It's carried with ammo using Federal 100 primers and Speer Gold Dot (short barrel) 135 gr HP's at ~885 fps. If it fires CCI primers, which I use as a check, I know I have a bunch of margin with Federal primers.

Visually checking the firing pin hits on fired cases doesn't really tell much that's usefull. Too many things happen after the initial hit that ignited the primer. If you want a better idea, drill the flash holes in some brass to ~ .110" and fire cases with primers only. The drilled flash holes will allow the primer to stay in the case and not set back and you'll see just the hit that ignites (or doesn't ignite if it's too light) the primer. If you play with the mainspring tension you'll probably be surpised how little primer "dent" it actually takes to make them go bang.

Of course your results may vary and it will be interesting to see what others have to say.

Interesting information. Thanks for posting!

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Centennial Every Day

For what it's worth, forum member, jmoln, mentioned in another thread that he had a M642 that had light primer strikes right out of the box. It was sent back to S&W and they said the problem was due to a "short firing pin."

Through PM's, jmoln was kind enough to tell me that the spent casing for that particular gun was dated, 6/20/2007. After he got the gun back from S&W the problem was no more.......

Thanks J!

My main goal in starting this thread was to try and dial in a time frame where guns might be susceptible to light primer strikes due to S&W's use of "shorter firing pins" and what S&W is currently offering as replacement parts.

Knowing all of the different types & lengths S&W used is good information but is a moot point if we can't readily buy them to retrofit guns that fall into that "short firing pin" time-frame.

That's why I ordered my new pins directly from S&W and not through a retailer, although most retailers I checked were out of stock when it came to J Frame Firing Pins.

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Ogy

Which "J Frame Firing Pin" was out of stock? The one common to all the current MIM FMFP CF guns, #22952? Or the older J Frame, the guns with the external crosspin below the rear sight, #21044?

The short firing pin issue applies to the (currently) #22952 firing pin type which is common to all the MIM FMFP CF guns. I'm not sure why you think it's some kind of mystery if there might be a problem. Just measure the firing pin. If it's a "short" one, replace it. But be aware the #22952 S&W firing pins have the same coloration from being heat treated you tried to make out to be an issue with the Apex firing pins.

I'm not here to debate, all of the J Frame Firing Pins were out of stock at both Brownell's & Midway about a month ago. Those are the two places I can remember, I also looked elsewhere because those two places were out of stock, with the same results.

My goal is to try and determine a general time-frame so people may not have to measure their firing pins if they fall under certain manufacturing dates. Example: currently, if I know a gun was made during 2007-2009 then it might be a good idea to check and see what length pin was used, especially if going to lighter springs. If the gun is current production then maybe it's not a part that a person, like Photoman or myself, would want to swap out just for the sake of swapping it out.

If they do decide to swap out their firing pin then they know what length was available at this point in time through S&W, which is considerably less expensive than some of the aftermarket pins.

I never tried to make the case hardening "oxide" on the Apex Firing Pins an issue, others, like yourself, did that. I was only trying to determine what it was and what role it played in the part's function. If, as you said, the finish is the same on both the Apex & S&W Pins then I was justified in asking because the two pins, as received, had totally different colorations. The Apex Pins (I have 5) had a deep copper, almost red coloration, which you don't see on the S&W Pins (I have 12 of the 22952's.)

I have polished up both types of pins, Apex & S&W and have only seen the "oxide" flake off of the Apex Pins while doing so. The dark coloration on the S&W Pins just polishes off as if you were removing patina due to ageing and not a "crusty type" of buildup, like on the Apex Pins.

I'm hoping to keep this thread informational and not have it turn into, to use your term in the Apex Thread, a bunch of "inter-net nonsense."

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Ogy

I'll try to take some time over the next few days and measure the pins in my Airweights. I've got a few of the later guns with the frame mounted firing pins.

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Centennial Every Day

Good idea. There is a known issue here. Speculating and/or assuming is not the way to go when you can measure and be sure.

Hello Ogy
Let me make a wild guess about the newer shorter firing pins.

My understanding of the old 1911 inertia firing pin was that it was protection against dropping pistol on the hammer and it firing. It needed the inertia of the hammer to go forward of the firing pin hole.

When I hold my 638-3 sideways up to my overhead light (empty) and lower the hammer a small amount of the firing pin is seen sticking out the hole. Not enough to fire the gun I assume.

My understanding of the old inertia firing pins was that they could never touch the primer and hammer at the same time.

S&W revolvers have so many safety features this is a ridiculous subject to me.

But just for curiosity -- if you have one with the shorter firing pin installed please hold it (empty) up to the light sideways and lower the hammer. With the hammer down can you see any of the firing pin. (I am betting you cannot).

If you have the model with the completely covered hammer you obviously cannot hold the hammer down flush after dropping the hammer.

However if you snap the hammer down and hold the trigger back while looking at the firing pin it is same thing.

(As long as the hammer has not been pushed back by the recoil spring you do not need to see the hammer to know it is completely down and the part of firing pin that is under the hammer is flush with the frame)

In the chamber/primer side. If you can see the firing pin a little outside the hole with the longer one, and not with the shorter one, we have found the mystery. They are just building numerous safety redundancies into the revolver.

(Maybe they are going to eventually lighten up on the hammer/trigger return spring & cam to make a lighter double action trigger?) (wild guess and/or gentle prod if anyone is listening).