Learning More About S&w Qc...

[Waltermitty]

So I’m installing this boffo new hammer assembly on the “B” gun and while things have gone together pretty well, I just can’t seem to get the same energy transfer into my highly technical calibration device (Bic Round Stic™)

The “A” gun with the Carmonized hammer and ~5 lb pull, poinks the (high) garage ceiling. I like this standard as a starting point because the gun has been running 100% when the primers are properly aligned (see Skip Chambers thread elsewhere).

So as I’m thinking and scratching and looking I notice that the firing pin doesn’t stick out as far on the “B” gun as it does on the “A” gun when the hammer is fully down. (what the….?) I bought both of these guns new, and as far as I know, both firing pins are stock.

I guess the next step is to tear both guns down to measure and compare the firing pins. I put the old hammer back in and saw the same effect, so it’s not the new hammer. I also used a flat piece of stock in place of the hammer to hold the pin flush with the frame on both guns and still see the difference.

Have any of you seen this before? My hypothesis is that either the overall length of the firing pin is less on the “B” or worse, the frame dimensions are different making for a longer firing pin channel. This is then stopping the energy transfer from the hammer to the pin prematurely, reducing total energy transfer.

How annoying. This is yet another reason why S&W needs 15 lbs of spring pressure to reliably light ammunition. This gun has been 100% reliable in the past as well, but I always had to dial in an additional 1 lb+ for it to run with the “A” gun. This is also probably another reason to just put an extended firing pin in all your action jobs.

So who’s making the best extended length firing pin these days?

RANDY LEE? Is yours ready for sale?

Edited April 19, 2006 by Waltermitty

[Round_Gun_Shooter]

Take the pin out of B, chuck it into the Dremel and spin it across a jewelers rouge impregnated cloth to shine up the large section of it. Then see how it works.

Regards,

[Waltermitty]

Take the pin out of B, chuck it into the Dremel and spin it across a jewelers rouge impregnated cloth to shine up the large section of it. Then see how it works.

Regards,

Thanks! That's a good suggestion. I did that after I relieved the notch in it to allow it to travel farther in the forward direction. It still doesn't show as much pin through the hole when the hammer is fully down; by a pretty big margin. I'll try to get some measurements tomorrow evening.

[D.carden]

Ken,

My new'st 625 had a shorter......but more "pointed" FP in it.

Why........Beats the hell out of me.

I did an action job on a 625 a few month's back and it was the same pointed one......????

[Round_Gun_Shooter]

Take the pin out of B, chuck it into the Dremel and spin it across a jewelers rouge impregnated cloth to shine up the large section of it. Then see how it works.

Regards,

Thanks! That's a good suggestion. I did that after I relieved the notch in it to allow it to travel farther in the forward direction. It still doesn't show as much pin through the hole when the hammer is fully down; by a pretty big margin. I'll try to get some measurements tomorrow evening.

I keep a few spare pins and springs, I have noticed that the smaller end lengths are not consistent in manufacture. Not a big difference, but enough. Relieving the slot doesn't help that unfortunately and can cause the pin to strike the bushing.

I still use C&S extended pins in my frame mounted pin guns with no problems. I also keep spares.

Good luck,

Edited April 12, 2006 by Round_Gun_Shooter

[Waltermitty]

Take the pin out of B, chuck it into the Dremel and spin it across a jewelers rouge impregnated cloth to shine up the large section of it. Then see how it works.

Regards,

Thanks! That's a good suggestion. I did that after I relieved the notch in it to allow it to travel farther in the forward direction. It still doesn't show as much pin through the hole when the hammer is fully down; by a pretty big margin. I'll try to get some measurements tomorrow evening.

I keep a few spare pins and springs, I have noticed that the smaller end lengths are not consistent in manufacture. Not a big difference, but enough. Relieving the slot doesn't help that unfortunately and can cause the pin to strike the bushing.

I still use C&S extended pins in my frame mounted pin guns with no problems. I also keep spares.

Good luck,

OK. So I've ordered the C&S pin from Brownells. Maybe it'll be here by the weekend.

[bountyhunter]

So I’m installing this boffo new hammer assembly on the “B” gun and while things have gone together pretty well, I just can’t seem to get the same energy transfer into my highly technical calibration device (Bic Round Stic™)

The “A” gun with the Carmonized hammer and ~5 lb pull, poinks the (high) garage ceiling. I like this standard as a starting point because the gun has been running 100% when the primers are properly aligned (see Skip Chambers thread elsewhere).

So as I’m thinking and scratching and looking I notice that the firing pin doesn’t stick out as far on the “B” gun as it does on the “A” gun when the hammer is fully down. (what the….?) I bought both of these guns new, and as far as I know, both firing pins are stock.

I guess the next step is to tear both guns down to measure and compare the firing pins. I put the old hammer back in and saw the same effect, so it’s not the new hammer. I also used a flat piece of stock in place of the hammer to hold the pin flush with the frame on both guns and still see the difference.

Have any of you seen this before? My hypothesis is that either the overall length of the firing pin is less on the “B” or worse, the frame dimensions are different making for a longer firing pin channel. This is then stopping the energy transfer from the hammer to the pin prematurely, reducing total energy transfer.

How annoying. This is yet another reason why S&W needs 15 lbs of spring pressure to reliably light ammunition. This gun has been 100% reliable in the past as well, but I always had to dial in an additional 1 lb+ for it to run with the “A” gun. This is also probably another reason to just put an extended firing pin in all your action jobs.

So who’s making the best extended length firing pin these days?

RANDY LEE? Is yours ready for sale?

Some info:

1) The new SW firing pin does not come through the breech plate as far as the hammer mounted firing pin (I realize that's not your question).

2) The above fact led C+S to make "extended length" firing pins which will protrude as far through as the old hammer mounted firing pins.

3) The quality of the three I bought from C+S was terrible. All needed smoothing and fitting. IMHO, they are junk.

4) My highly unscientific testing proved the C+S pins did not strike any more effectively than stock SW pins, or allow me to use a lighter mainspring:

Hence, it's the energy applied to the pin, not how far it's head pops out (assuming it pops out far enough to do the job).

5) If you have a pin you think isn't coming out, rework the trailing edge of the "notch" for the retaining pin that keeps it in the channel as that is probably the limiter. If not, shave the front of the FP body that contacts the frame.

If you really want a long one, get the C+S pin.

My wife lies to me and tells me length doesn't matter, but on firing pins it looks like she's right.

[Waltermitty]

Some info:

1) The new SW firing pin does not come through the breech plate as far as the hammer mounted firing pin (I realize that's not your question).

2) The above fact led C+S to make "extended length" firing pins which will protrude as far through as the old hammer mounted firing pins.

3) The quality of the three I bought from C+S was terrible. All needed smoothing and fitting. IMHO, they are junk.

4) My highly unscientific testing proved the C+S pins did not strike any more effectively than stock SW pins, or allow me to use a lighter mainspring:

Hence, it's the energy applied to the pin, not how far it's head pops out (assuming it pops out far enough to do the job).

5) If you have a pin you think isn't coming out, rework the trailing edge of the "notch" for the retaining pin that keeps it in the channel as that is probably the limiter. If not, shave the front of the FP body that contacts the frame.

If you really want a long one, get the C+S pin.

My wife lies to me and tells me length doesn't matter, but on firing pins it looks like she's right.

Last week it would have been a hard assignment to get me to order an extended firing pin. I had proven to myself on my "A" gun that the stock FP length was just fine and all this extended FP talk was hooey. Today I know less than I did last week. Until I get some additional measurements done I *still* don't know what is different between these two guns. They are both 625-8's purchased about two years apart. I'm really hoping the firing pin is shorter as Dan and RGS have observed.

While the extension through the hole has been my way of describing the situation, my real concern is at the other end of the pin. If the face of the hammer is bottoming out on the frame before the pin can absorb/transfer the energy in the strike, then it will always have to be struck harder in the shorter contact time available. Likewise, if S&W has been trying to move stealthly towards an inertia type FP system, the strike will have to be very high indeed to get reliable ignition with such a small FP. I think the "Old design" creates an overlap period when the primer, FP, and hammer are all physically connected and energy is being transferred all the way from the hammer spring through to the primer anvil.

When I take the firing pin spring and retaining pin out and drop the FP in the FP channel, it falls through far enough to stick into the chamber on the cylinder, so I know I have enough length on the tip. It would probably be more accurate to say the FP is not sticking out enough in the back at rest.

I did take some material out of the notch on the FP, but there's not much material there to work with and still leave a full FP body diameter to guide the pin. I may take another whack at it, but for the amount of length I'm looking to gain I am not hopeful this will be of much benefit. And it still doesn't address my desire to have zero clearance in the system between the primer anvil and the hammer spring.

[pskys2]

I've been using the c&s fp with no problem. The original in my 625, which was pointed, broke after a year of dry firing (I do use empties). I've tried 3 of them and they all fit and worked with no problem (1 in use & 2 spares w/springs). Knock, Knock, Knock on Wood!!! Hope my luck holds.

If you're talking of relieving the "Back" of the notch that the retaining pin fits thru, IMHO that won't help anything. That should be relieved enough or that little pin will snap like a twig.

The difference is probably between the face that contacts the back of the recoil shield and the "Tip" of the Firing Pin.

So, if the tip measures the same you may have to look into the fp tunnel there could be some trash in there.

I'll try to remember to measure a c&s this weekend.

[10mmdave]

Okay...I gotta add something to this...........

So what do folks think, get the tip of the firing pin closer to the primer so when the

hammer strikes it has a short distance to go or do folks think maybe some space

between the firing pin and primer to build up more "whack" from the hammer ???

I bring this up only because of a mis-firing 627 with an extended FP, the tip of the pin was

barely breaching the FP bushing and this gun was having mis-fires. I relieved the FRONT

of the retaining slot so the FP would sit back in the FP tunnel a little more, gun doesn't seem

to mis-fire anymore but I also snipped a half coil off the FP spring.

(I really need to only do one thing at a time )

It reminds me of the Kill Bill 2 flick and Uma getting out of the coffin

Not everybody can break a board from 0-4 inches away but most of us can from 18-24 !?

(and I'm talking thin boards here, don't try this at home kids)

Okay, hope I didn't confuse the thread, if I did sorry.

[Bones]

I'm having the same issues with new and old style 10s.

The same springs that make my 10-8 or 13-2 (hammer mounted pin) go bang every time do not do that in either of my new 10-14s (frame mounted pins). The C&S x-pin did not alleviate the situations, even after polishing/pointing.

Oddly enough the difference I measured in FP penetration into the frame window is 0.015", the exact same length difference between the stock and C&S pins.

I'm stymied.

What about the firing pin return spring length and compression force?

Edited April 12, 2006 by Bones

[Waltermitty]

10MM,

I vote that the coil cut made the difference, oh and you made the FP lighter by removing material from it. If the FP was heavier I could see the need for a longer "acceleration gap", but if the end of the FP is at least flush with the bushing that should be enough gap. BTW, I cut my FP return spring as well.

Bones,

One of the problems I saw building up both of my 625-8's was that the hammers were hitting the sides of the frame. Can you see any bright marks on either side of your hammers when disassembled? If yes, you'll have to deal with that interference first. There should only be (light) contact at the hub. I also check free travel on the hammers by taking everything out of the gun except the hammer and the cylinder stop. Then install the side plate. Roll the gun around through the arc of the hammer. It should fall freely back and forth as you rotate the gun. If it does not you'll have to figure out why. One of the reasons I bought a new hammer assembly from a well-known source was the piss-poor fit of the S&W hammer. To keep the hammer from hitting the frame on my "A" gun I installed 3 shims, this made the hammer too tight in the frame. So my choice was to grind material out of the frame, recontour the left side of the hammer, or take material off of the right side of the hammer. I stoned quite a bit of material off of the S&W hammer and used shims to eventually get a hammer assembly that would swing freely and stay centered in the frame. I easily put 20 hours into that little exercise alone.

So, yes, cutting a turn off of the FP return spring may help, but it could also be something else. Do you know what your trigger pull is now?

[Bones]

I think you've nailed it Walter. I will check those fits in more detail this weekend.

Thanks,

Craig

[sargenv]

I'm not sure if this has any bearing or not but here goes. I had Dan Carden work on my 610. He worked over the action and did a hell of a job. He told me that when he used a feeler gauge, there was I think .005" to .006" play between the firing pin tip and the cartridge case fully seated in the cylinder with moons installed. I was getting about 98% ignition with the TK .040" moons and probably 70% with the .034" clips. Dan had put a nice cone on the pin, but it was still not 100%. I purchased and dropped in a C&S extended pin, and it has since run 100% with Federal primers and about 98% with Winchester primers. It will occasionally not fire the Winchesters. I was shooting the Winchesters as practice ammo, so long as it fires 100% with the Federals that's all I care about. I have not tried Remington primers as yet but probably will at some point since I have them in my inventory.

It appears that the extended pin really has made a difference to me. So long as I feed it Federal primed loads, it will always go "bang".

Vince

[Waltermitty]

I'm not sure if this has any bearing or not but here goes. I had Dan Carden work on my 610. He worked over the action and did a hell of a job. He told me that when he used a feeler gauge, there was I think .005" to .006" play between the firing pin tip and the cartridge case fully seated in the cylinder with moons installed. I was getting about 98% ignition with the TK .040" moons and probably 70% with the .034" clips. Dan had put a nice cone on the pin, but it was still not 100%. I purchased and dropped in a C&S extended pin, and it has since run 100% with Federal primers and about 98% with Winchester primers. It will occasionally not fire the Winchesters. I was shooting the Winchesters as practice ammo, so long as it fires 100% with the Federals that's all I care about. I have not tried Remington primers as yet but probably will at some point since I have them in my inventory.

It appears that the extended pin really has made a difference to me. So long as I feed it Federal primed loads, it will always go "bang".

Vince

I hope I get the same result as you did. I converted to Federalism as well and keep a stock of 150's on hand.

Your comment reminded me about another clearance that adds in as well. I seat my primers DEEP. I measure .006"+ below the case head. Randy said he seats them to .010". That number is added to the .005"-.006" headspace the gun needs to move. Add that to however much the FP tip is below flush and that's how much the pin has to move before it touches the primer.

[Waltermitty]

About 9:15pm...

Welp, the "B" gun FP is .010" shorter overall than the FP in the "A" gun. I didn't take any other dimensions to see where the variance is, .010" is too much difference on what I think should be a part with a tolerance of no more than +/- .002". I'll stalk the postman waiting for my Brownells envelope and start again then.

Let this be a lesson to the rest of you to just send your guns to Randy.....

[Carmoney]

Excellent......nearly everybody I compete against is using a Chlilinder & Schlide extended firing pin.....that is beautiful music to my ears.......

Edited April 13, 2006 by Carmoney

[D.carden]

Excellent......nearly everybody I compete against is using a Chlilinder & Schlide extended firing pin.....that is beautiful music to my ears.......

Have another Scotch Mike.........Your sound'n rather Happy out there.....Now go to bed.!!

[Waltermitty]

Excellent......nearly everybody I compete against is using a Chlilinder & Schlide extended firing pin.....that is beautiful music to my ears.......

Have another Scotch Mike.........Your sound'n rather Happy out there.....Now go to bed.!!

Maybe he's delirious with the Mumps?

http://www.msnbc.msn.com/id/12097831/from/RSS/

You and Sam feeling OK? Mike?

[Carmoney]

No Mumps so far. Sounds like it's hitting the college campuses hard.

(Ironic--back when I was in undergrad, many of us were struck with a drastic case of the Pumps....I believe I'm immune these days....)

[Waltermitty]

No Mumps so far. Sounds like it's hitting the college campuses hard.

(Ironic--back when I was in undergrad, many of us were struck with a drastic case of the Pumps....I believe I'm immune these days....)

Pumps? Isn't that a high heel shoe with a closed toe? Are you sure that's something you want us to know?

http://www.classicpumps.com/

[bountyhunter]

I did take some material out of the notch on the FP, but there's not much material there to work with and still leave a full FP body diameter to guide the pin. I may take another whack at it,

To get more forward extension on the tip, you want to remove material on the rear most face of the notch in the FP (the one that the retaining pin hits as the FP comes forward).

If I recall, it's machined with "flat faces" so you can get more forward extension just by rounding the rear face cut to match the curve of the retaining pin.

I'm having the same issues with new and old style 10s.

The same springs that make my 10-8 or 13-2 (hammer mounted pin) go bang every time do not do that in either of my new 10-14s (frame mounted pins). The C&S x-pin did not alleviate the situations, even after polishing/pointing.

Oddly enough the difference I measured in FP penetration into the frame window is 0.015", the exact same length difference between the stock and C&S pins.

I'm stymied.

What about the firing pin return spring length and compression force?

That spring definitely eats up some striking energy. I am 99.999% sure moving the "rest" position" of the FP slightly closer to the hammer will accomplish nothing. The FP compresses that spring when you install it, the difference in compression distance by moving the rest position back .015" is virtually nothing compared to how far the spring is already compresed and how far it has to be driven to engage the primer.

As for penetration depth: I saw no difference in required hammer force between the shorter SW and longer C+S. I think the main factor is energy, not depth since the primer is stopping the motion of the pin anyway, it never reaches it's farthest point of extension as it does when there is no round there.

I'm not convinced having the hammer contact the FP head sooner in it's stroke would deliver more energy, I suspect it would deliver less. The collision of the hammer and FP is a highly ELASTIC collision where the two metal pieces transfer energy pretty efficiently. The FP head is compressed and "bounces off" the hammer face. The hammer's velocity is higher nearer the frame, so I suspect maximum energy transfer would occur as close as possible to the frame because energy is proportional to the velocity (squared).

Edited April 13, 2006 by bountyhunter

[Carmoney]

I agree with Bounty.

Except for the rare occasion where the stock firing pin truly has insufficient protrusion, the C&S product is purely a placebo. Randy has suggested the sharper profile might be a little better for ignition--OK fine, then sharpen the stock pin if you want.

Human beings do love their placebos.....the next thing we'll see is a special deluxe version of the C&S pin that has been "cryo-treated".........

[Randy Lee]

Hi guys,

Smith in their litigant fearing wisdom shortened the firing pins by .010". The pins are Titanium as well- something to do with cost and the CA drop test.

The new firing pins work okay at factory weight trigger pulls using non- Wolff mainsprings.

On the 625's I've noticed that the new pins can prove unreliable in the 4.0-4.5 lb range, especially if the brass cases are on the short side.

Using the C&S pins tended to eliminate the ignition problem I experienced with the 625s. I end up modifying the pins, which usually takes me 20+ minutes. It doesn't sound like much time, but extrapolating that out to 300 some-odd guns gets old fast.

The other problem is that the extended firing pin can push the firing pin bushing forward if you are running a heavy hammer fall weight.

The drawings for the new firing pin are ready to go off to the machine shop and will be there next week. I personally believe that the firing pin needs to have a bit more weight to them than the Ti versions offer.

I remember having ignition problems with Ti firing pins in the 1911s which went away once the steel versions were inserted.

[Carmoney]

Smith in their litigant fearing wisdom shortened the firing pins by .010".

OK, you lost me here. How could shortening the FP reduce the chance of litigation?