Cylinder and Slide extended firing pin broke

[imashooter2]

Broke on me during a match today. Luckily I had the take out factory pin in my bag so I swapped it out and finished the match. Less than 2K rounds on it and no dry fire without snap caps.

Add me to the list of those who've learned.

[Carmoney]

Man, it is SO tempting to say "I told you so" to all those who wanted to argue with me about this.

But that would be pretty childish, so I won't.....

[hearthco]

Word in Morro Bat is that Apex fireing pin comming soon.

The rumor is that dry fire without snapcap will work.

Live from Baywood Park. Hearthco

[Evil Dog]

New guy here..... what is the purpose of the extended firing pin? How does it work better than factory?

[imashooter2]

Well, I bought it on the notion that it would put a deeper dent in the primer and help set off what would otherwise have been a marginal hit. In practice I found that after it breaks off, the gun fails to fire 100% of the time.

[Carmoney]

If you stop and really think about it, a longer pin does not--cannot--hit the primer harder. It's transferring the exact same amount of energy. So, really, the only way a longer pin could possibly hit deeper is if the factory pin it replaces has insufficient protrusion or the gun has developed a little too much headspace.

Plain and simple, it's marketing and nothing more. Puts money in Bill's pocketbook. And then he doesn't even bother to make them right. They often don't fit right, and then they frickin' break because they're not hardened properly.

I'll bet the meaningful feature of the "Randy Pin" will be a slightly redesigned nose profile to maximize energy transfer (i.e. it will be a little "sharper" than a stock pin).......I have no doubt it will be the highest possible quality, let's hope it doesn't cost as much as an pair of big butt grips, huh??

Edited August 6, 2007 by Carmoney

[Tom E]

C&S extended firing pins seem to do one thing: break. Interesting to note tho that the S&W firings pins I've bought recently are longer than the one that came in my 625-8. There seems to have been a running change.

Edited August 6, 2007 by Tom E

[Evil Dog]

My K-38 has the same firing pin that the factory installed in 1954. It has never failed to go bang when the trigger is pulled. Don't see much reason to change it.

[professor]

The factory firing pin in my 686 gave light, inconsistent hits from the start. Headspacing was within specs. What I found was...

(1) Hammer was hitting the sloped portion of the frame below the firing pin significantly before hitting the firing pin. I don't think enough energy was transferred to the firing pin to drive it forward against the restraining rebound spring.

Once that was fixed by increasing the distance that the flat part of the hammer would be in contact with the firing pin, I still had...

(2) Insufficient pin protrusion through the blast shield, resulting in consistently light hits.

So I put in a C&S extended firing pin, and [knock on wood] no problems with bullets going off since then. [2 years now] I did chuck the extended pin in my trusty Dremel and polish it so there were no hangups in the blast shield or hammer impact end of the firing pin channel. The BIC-o-meter indicates significantly better hits on a primer with the extended pin than with the factory pin, with no change in the mainspring or trigger pull. Yeah, I'll be sure to carry around a spare one for if and when this one breaks.

I would speculate that a possible reason for these pins breaking is a buildup of gunk in the firing pin channel or a broken firing pin rebound spring. Either could cause the pin to stick in its forward position, extended enough to still be in the zone where they could be stuck in the primer or hit by the head of the next round when the cylinder rotates. Even with the extended pin, there's normally enough clearance for the pin to get out of the way of getting hit by anything on the rotating cylinder.

If you stop and really think about it, a longer pin does not--cannot--hit the primer harder. It's transferring the exact same amount of energy. So, really, the only way a longer pin could possibly hit deeper is if the factory pin it replaces has insufficient protrusion or the gun has developed a little too much headspace.

I'd like to point out that the extended pin does have more mass than the factory pin, because it is slightly longer. Although the hammer may hit the end of the pins with the same exact speed, the energy transferred to the pins is also a function of the contact time and the inertia of the two pins. With its greater mass [inertia], the extended firing pin will take slightly longer to react to getting hit by the hammer. It will therefore be in contact with the hammer longer, and gain more kinetic energy than the factory pin. That kinetic energy will compress the rebound spring more than a factor pin with lower kinetic energy, and there will be more energy left to hit the primer.

And the kinetic energy in the moving hammer that hits these two pins is so great the energy transferred to either pin is negligible by comparison.

Does anybody make these firing pins out of tungsten???

[Tom E]

What I found was...

(1) Hammer was hitting the sloped portion of the frame below the firing pin significantly before hitting the firing pin.

What?

FWIW FMFP lengths:

C&S .510"

newer S&W .495"

older S&W .485"

I assumed you don't dry fire FMFP guns w/out snap caps because it will beat the firing pin spring and/or bushing to death. It really shouldn't break the firing pin tip.

I really like Carmoney's thought about thinning the firing pin tip.

C&S pins seem to have an ill chosen alloy/heat treat.

Edited August 6, 2007 by Tom E

[All-Gator]

The real purpose of a long firing pin is so that it can be fitted with the tip flush with the breechface. This precludes primer flow into the hole being sheared off as the case is ejected and jamming the pin either forward on the next round (resulting in the weapon going auto...this can be fun with a 30-round big stick) or to the rear (resulting in no bang). This was important with 175 PowerFactor .38 supers, 9x23's, major 9's, etc.

I've had these in all of my competition guns for years and years and many, many, many rounds with never a failure...but they were always fitted and never just dropped in.

[whizz]

In my experience the smoothness of the tip is of pretty high importance. A mirror polish will easier ignite then a more rough one. If I have ignition trouble (and this is irrespective of type of firearm) the first thing I check is if the tip of the firing pin is smooth and without dents. If it's not I polish it. Polishing does not mean reshaping or removing of any significant amount of material. In theory a scratched or uneven surface of the tip looses "a lot" of energy when hitting the metal of the primer and forcing the scratches or dents through the metal. A well polished surface on the contrary deforms the primer metal easier with less friction. It sounds far fetched but I learned this trick from a gunsmith several years ago and it has so far cured ignition problems on one shotgun, one revolver and one pistol I own.

[Carmoney]

The real purpose of a long firing pin is so that it can be fitted with the tip flush with the breechface. This precludes primer flow into the hole being sheared off as the case is ejected and jamming the pin either forward on the next round (resulting in the weapon going auto...this can be fun with a 30-round big stick) or to the rear (resulting in no bang). This was important with 175 PowerFactor .38 supers, 9x23's, major 9's, etc.

I've had these in all of my competition guns for years and years and many, many, many rounds with never a failure...but they were always fitted and never just dropped in.

All-gator, I know you're trying to be helpful, but you must have missed the fact that we're talking about firing pins on revolvers in this thread. Whole different ballgame.

[All-Gator]

Damn, this getting old ain't fun. As my grandkids say, "My bad."

Sorry 'bout that.

A-G

[Carmoney]

A-G, as your grandkids say, "It's all good."

[revchuck]

Damn, this getting old ain't fun.

Beats the alternative!

[bountyhunter]

New guy here..... what is the purpose of the extended firing pin? How does it work better than factory?

It extends slightly farther out when struck. The myth is that ill give better ignition, in reality it is the energy of the strike, not how far the tip will protrude when dry fired.

My gripe with the C+S pins is all the ones I got were poorly made and had to be trimmed because they were binding.... they also extended too far out at rest and dragged on the primers (more trimming needed).

And after very careful measurements with reduced power mainsprings, I did not see any advantage at all for striking energy transferred by the pin.

They are worthless.

[bountyhunter]

And the kinetic energy in the moving hammer that hits these two pins is so great the energy transferred to either pin is negligible by comparison.

hence the reason there was no difference in performance.

[professor]

And the kinetic energy in the moving hammer that hits these two pins is so great the energy transferred to either pin is negligible by comparison.

hence the reason there was no difference in performance.

You're misinterpreting my statement. The moving hammer usually has so much kinetic energy that the inertia of the two pins, and the energy transferred to them, doesn't slow down the HAMMER any. However, as you reduce the trigger pull weight, you also reduce the kinetic energy stored in the hammer, and you'll reach a point where the energy transferred to the firing pin is insufficient to set off primers.

However, there is significantly more kinetic energy transferred to the extended pin versus the factory length pin. That energy in the extended pin is available to impact the primer harder, travel further [across a wider than normal cylinder end gap], and more fully depress the firing pin recoil spring. The result can be improved primer ignition.

Please note that my Bic-o-meter results do indicate improved performance in my gun, all things being equal except the two firing pins.

Also note that my experience is with a 686, shooting 38 Spl brass with Federal #100 Small Pistol Primers. I'm not dealing with a 625 shooting ACP 45 brass with Large Pistol Primers.

Now would someone please explain to me just how and where the C&S firing pins are breaking. Are the firing pin tips snapping off? Has anyone examined the last primer that was fired before the pin broke? Are the firing pins piercing the primer cup and getting caught so the pin can't recoil? Are the rebound springs failing, allowing the firing pin to jam in the blast shield so it's stuck in the forward position? Are your particular C&S pins jamming in the firing pin shield due to an overly thick shaft?

Just maybe the pin failure is an "unintended consequence" of extra stress to the rebound spring, rather than a basic defect in the pin itself.

[Carmoney]

However, there is significantly more kinetic energy transferred to the extended pin versus the factory length pin. That energy in the extended pin is available to impact the primer harder, travel further [across a wider than normal cylinder end gap], and more fully depress the firing pin recoil spring. The result can be improved primer ignition.

No disrespect intended, but I do not believe this would be true. The transfer of energy to the firing pin would have nothing whatsoever to do with the length of the pin--we can agree on that much, I think--it would simply be a function of the energy stored in the mainspring under tension. And although I'm no physicist, I believe a firing pin with more mass (like the C&S product) would absorb more of that stored energy to take it from a resting position into motion than a firing pin with less mass. Seems to me this is the same reason many of us cut down our hammers, the reduced mass results in faster lock time because less energy is lost in getting the hammer moving from its resting state at the rear of the hammer travel arc.

[Carmoney]

(It just occurred to me that I was an English major, and now I'm arguing with a guy who goes by the name "Professor" about a physics problem! I may be getting myself in a lot of trouble here.....)

[RePete]

I majored in Chem and had a good working knowledge of Physics, but that was 41 years ago in England, but now I'm a Vehicle Tech, both auto and heavy equipment, so I'm not going to comment on the Physics side.

That being said, I installed a C&S pin in my 625 and had no end of problems with Federal primers (mainly missfires, and I have the factory mainsprng), but with Winchester primers I've had zero problems. I do recommend it at this time and reserve the right to change my mind.

Carmoney:

I have performed the hammer lightening as of yet. I'm 3000 miles from home right now and won't be back for a couple of weeks. Once I retire (end of September), I'll get my a$$ in gear.

[Carmoney]

Setting the science issues aside for a sec, the QC problems with the extended pin are enough to put it out of contention for a revolver used for any sort of serious purpose (including serious competition), in my view.

How many more people have to report in that these frickin' things break before you guys will accept reality??

[Randy Lee]

Hi guys,

Thought my chain would stretch from the bench to the computer.

A couple of my thoughts on firing pins in the Smith revolvers:

First is the length of the firing pin. The factory up until recently has been sending out firing pins that measure .485 or less. I've had several new guns that wouldn't fire factory ammo out of the box as a result. .495 or greater length would be my preference.

Material comes to mind next. The factory uses Ti pins and I suspect that the short pin length and material were chosen for the drop test criteria for sales in some states (CA comes to mind since I'm still here). Combine a short pin, headspace at the larger end of the spectrum and the factory firing pin spring to slow the pin before it deforms the primer and you have iffy ignition. Because of the minimal mass of the Ti short pins, they will tend to decelerate faster (f/pin spring compression) than their steel counterparts. Momentum is very important (at least to me). There is no question in my mind that people who have had ignition issues with the factory .485 pins who replaced them with C&S pins found the problems went away- at least for the average recreational shooter (Mike, you can probably guess where I'm going with this). The mass of the steel factory pins as well as the C&S pins will increase the time interval that the pin tip meets the primer cup and deforms it to the point that the priming compounds mix. My preference is for a high quality steel that is properly heat treated.

I use the C&S pins in my competition trigger work simply because the old steel factory ones are scarce. Up until now they have been to only readily available steel pins. I figure that the # of pins I've bought and installed in customer guns has at the very least paid for a nice meal for Bill and his crew ( no disrespect to Bill and Cylinder and Slide intended).

So onto the problems I've encountered with the C&S pins. First is the snap cap issue. The factory firing pin's maximum forward travel is limited by the retaining pin in the frame. This prevents damage to the firing pin bushing in the frame, the f/p spring and the pin itself. The C&S pins typically do not stop in the same manner. I believe at least some of the breakage is due to the fillet (increasing taper of the pin tip) coming into contact with the f/p bushing hole under dry fire (sometimes even once will do it) conditions. I've had some customer pins break even with snap caps- as not all caps are created equal, and their effectivenes degrades over time. my personal belief is that a good percentage of the breakage could be reduced by one design change in the area of the retaining pin cut.

Another issue that many do not think about pertaining to revolver firing pin design are the torsional forces at play in high speed revo DA shooting. In many cases the timing of when the cylinder stops relative to when the firing pin is imbedded in the primer do not coincide. If the gun is off time, the cylinder is still rotating as the f/p is imbedding into the primer. The result is a lateral force that the pin is ill equipped to handle. The longer the firing pin, the more torque it will be subjected to. I suspect some percentage of the breakages are attributable to this .

I've wanted to produce my firing pins for a while now. Other than test firing guns, dry fire practice is about all I can do these days and I'd like to be able to dry fire without the fear of breakage. And my A-Zoom snap caps are so beat up that 2 of the .38 spl ones got pushed out the front of the cylinder...

Edited August 8, 2007 by Randy Lee

[Tom E]

" Because of the minimal mass of the Ti short pins, they will tend to decelerate faster (f/pin spring compression) than their steel counterparts. Momentum is very important (at least to me)."

Call me dense because this I don't quite understand.

With the trigger held back the hammer is firmly in contact with the firing pin, holding it as protruded as it's length allows. This isn't a true inertial firing pin. (A 1911 Colt having an inertial pin where the firing pin does not protrude with the hammer fully forward.)

That said, the hammer comes forward, contacts the firing pin and cotinues forward WITH the firing pin until the hammer contacts the frame and stops. In terms of momentum aren't we dealing with the effective weight of the hammer and firing pin?

The depth of the primer dents leads me to believe the firing pin (only 6 grains for S&W, 10.5 for C&S) does not continue forward after the hammer stops.

Seems the hammer/pin needs enough momentum to adequately dent the primer and also enough velocity to get it to ignite. Two seperate but related issues.

Aren't we lightening our hammers to get back the velocity we lose when we lighten the hammer spring? Retaining velocity but actually losing momentum?

What am I missing? Tom