bountyhunter
Member
- Joined
- Jan 8, 2002
- Messages
- 1,862
- Reaction score
- 464
You came in very late to the thread. All the smarter posters gave up long ago bothering to answer his posts.
Firing Pin Failures....MIM!!!???
- Thread starter Ultima-Ratio
- Start date
You came in very late to the thread. All the smarter posters gave up long ago bothering to answer his posts.
Stophel
Member
Bountyhunter, thanks for the explanation of just what MIM actually is. It seems it is basically formed "dry", and then melted inside the mould (rather than poured into the mould as with normal casting). I wasn't sure just how it was done before.
Oh, and please excuse my ignorance, but just what the heck is FMFP???
Oh, and please excuse my ignorance, but just what the heck is FMFP???
imashooter2
Member
Frame Mounted Firing Pin as opposed to the older hammer mounted pins.
bountyhunter
Member
- Joined
- Jan 8, 2002
- Messages
- 1,862
- Reaction score
- 464
Not exactly: metal powder is mixed with polymer binders (basically glue to hold it together) and then it is force injected into the mold under pressure. The part is then taken out of the mold and is what they call a "green" part. As I understand it, the part has no strength and can be crumbled by hand since none of the metal particles have yet to be fused. The green part is then heated in the firing process during which the glue is burned out and the metal particles fuse into solid metal. The part also shrinks some during the firing step but shrinks in a controlled and completely predictable way which allows for holding very precise tolerances on the finished piece.
Randy Lee
Member
Greetings all,
I wanted to share some of my humble observations regarding firing pins. First and foremost, my pins are made from 17-4PH stainless steel round stock. I believe a forged firing pin would be prohibitively expensive to make.
As far as factory Ti firing pins failing, there is no question that they do. The caveat to that is that any pin will fail given the right circumstances. Chipping and fracturing of the factory pins is commonly seen in guns firing either fast recoiling high velocity ammo or heavy recoiling big bore magnums. I have seen evidence of failure in both the Scandium J-framed guns as well as the .460-500 X-frames.
One of the causes of this is what is known as a contra-cou event. When the firing pin embeds in the primer and pressure builds(in the hotter loads), the primer is the first thing to move rearwards. This begins to push the firing pin rearwards before the cartridge case begins to shift back(If you fire a primed case without any bullet or powder on it you can see measurable primer shift.) Once the bullet leaves the case and begins to travel towards the forcing cone, the case then follows it's rearward path and slams against the recoil plate or breech face.
With heavy or fast recoiling loads, the firing pin can actually push back against the hammer with enough force to have it lose contact with the firing pin and slap back down. It is a nearly instantaneous event, but it does happen.
In a nutshell, the firing pin gets hammered in both directions. The factory Ti firing pins were designed to pass a drop test and not a contra-cou event. With the conical shape seen on current factory firing pins this phenomenon concentrates an excessive amount of force on it's tip. Most of the failures I have seen are chipping or fractures of the tip, although I would not be surprised if breakage occured elsewhere along the pin shaft.
For such applications I believe the firing pin tip should be a full radius dome and made of a shock resistant steel for the sake of longevity. At least for the stout magnums that will be shot with any regularity.
I wanted to share some of my humble observations regarding firing pins. First and foremost, my pins are made from 17-4PH stainless steel round stock. I believe a forged firing pin would be prohibitively expensive to make.
As far as factory Ti firing pins failing, there is no question that they do. The caveat to that is that any pin will fail given the right circumstances. Chipping and fracturing of the factory pins is commonly seen in guns firing either fast recoiling high velocity ammo or heavy recoiling big bore magnums. I have seen evidence of failure in both the Scandium J-framed guns as well as the .460-500 X-frames.
One of the causes of this is what is known as a contra-cou event. When the firing pin embeds in the primer and pressure builds(in the hotter loads), the primer is the first thing to move rearwards. This begins to push the firing pin rearwards before the cartridge case begins to shift back(If you fire a primed case without any bullet or powder on it you can see measurable primer shift.) Once the bullet leaves the case and begins to travel towards the forcing cone, the case then follows it's rearward path and slams against the recoil plate or breech face.
With heavy or fast recoiling loads, the firing pin can actually push back against the hammer with enough force to have it lose contact with the firing pin and slap back down. It is a nearly instantaneous event, but it does happen.
In a nutshell, the firing pin gets hammered in both directions. The factory Ti firing pins were designed to pass a drop test and not a contra-cou event. With the conical shape seen on current factory firing pins this phenomenon concentrates an excessive amount of force on it's tip. Most of the failures I have seen are chipping or fractures of the tip, although I would not be surprised if breakage occured elsewhere along the pin shaft.
For such applications I believe the firing pin tip should be a full radius dome and made of a shock resistant steel for the sake of longevity. At least for the stout magnums that will be shot with any regularity.
tomcatt51
Member
Ever seen high frame rate slow motion film/video of the hammer when the gun is fired? I've always assumed the hammer bounced a couple times during the process.
Randy Lee
Member
Tomcatt51,
I have seen a few, but none that have focused on this event and none with the 500 or the j-frame Sc guns where this was the focus.
I have however seen cases where the case hardened surface of a hammer was penetrated by the back face of a firing pin and resulted in a severe crater. This is why the shape of the firing pin strike face can be critical as well as the tip. It's amazing what I learned in the process of developing and testing my pin.
I have seen a few, but none that have focused on this event and none with the 500 or the j-frame Sc guns where this was the focus.
I have however seen cases where the case hardened surface of a hammer was penetrated by the back face of a firing pin and resulted in a severe crater. This is why the shape of the firing pin strike face can be critical as well as the tip. It's amazing what I learned in the process of developing and testing my pin.
bountyhunter
Member
- Joined
- Jan 8, 2002
- Messages
- 1,862
- Reaction score
- 464
Thanks for the explanation. I'm not sure I understand this or why the shorter pins in a SW revo would be prone to break. The firing pins in autos are much longer and subject to the same physics. When the round fires, the primer always flows backward against the head of the firing pin. In autos with light recoil/hammer springs that unlock too quickly, the case is dragged out before the tip of the FP retracts fully and the primer shows the "wipe" track from it.
I understand the FP in the SW revo might get a rearward whack that would "bounce" the hammer from contact, and then the hammer would hit it again but the second hit would have less force than the first initial hit.
I am having rouble seeing why the primer backflow would be so lethal to the firing pin in the revo, when the much longer pins in autos hardly ever fail.
Randy Lee
Member
There are a couple of reasons that I can think of. First, the conical tip has a much smaller impact surface area, so the stresses on the tip tend to be a bit more of an issue. In the case of the revolver (using hotter loads anyways)the headspacing can be a bit more generous allowing the primer to move back farther and a bit faster.
In a 1911 the mass of the firing pin, associated parts and therefore the inertial events are spread out over a longer time interval. Back when major power factor was 175 in IPSC and titanium firing pins were played with, chipping of the tip was a common experience. I have seen a lot of pierced primers as a result of a chipped 1911 Ti firing pin. I think both the revolver and the 1911 firing dynamics have vastly different (and directional) forces at work. Too complex for me to analyze with my wee little brain anyways.
A couple of other factors come into play as well. For guns firied DA, there are rotational forces which can apply stresses to the pin. In the case of the revolver pin(with the hammer down) the protrusion is at some nominal length sticking into the primer. At the first impact, energy has to be absorbed as the primer cup deforms. In the following contra-cou events typically the anvil of the primer is pressing in against the cup from the opposite direction. So the impact force of these secondary or perhaps even tertiary bounces may not be as insubstantial as we think.
As a sidebar, I have only seen one of the factory round tip steel firing pins chip. I honestly think material selection and tip geometry plays a critical role here.
In a 1911 the mass of the firing pin, associated parts and therefore the inertial events are spread out over a longer time interval. Back when major power factor was 175 in IPSC and titanium firing pins were played with, chipping of the tip was a common experience. I have seen a lot of pierced primers as a result of a chipped 1911 Ti firing pin. I think both the revolver and the 1911 firing dynamics have vastly different (and directional) forces at work. Too complex for me to analyze with my wee little brain anyways.
A couple of other factors come into play as well. For guns firied DA, there are rotational forces which can apply stresses to the pin. In the case of the revolver pin(with the hammer down) the protrusion is at some nominal length sticking into the primer. At the first impact, energy has to be absorbed as the primer cup deforms. In the following contra-cou events typically the anvil of the primer is pressing in against the cup from the opposite direction. So the impact force of these secondary or perhaps even tertiary bounces may not be as insubstantial as we think.
As a sidebar, I have only seen one of the factory round tip steel firing pins chip. I honestly think material selection and tip geometry plays a critical role here.
bountyhunter
Member
- Joined
- Jan 8, 2002
- Messages
- 1,862
- Reaction score
- 464
Thanks for the info. I never looked really close at the shape of the tip of the FP, so I never knew it was conical. Couldn't the stock FP tips re radiused out a bit to make them rounder on the end?
Randy Lee
Member
Possibly. But I know that the short conical Ti pins of late have a surface treatment to reduce abrasive wear which could be removed and expose raw Ti alloy. Smith does have some of the .49+ firing pins sitting in inventory and all of those that I have seen have spherical tips.
tomcatt51
Member
FWIW the only S&W conical tip pin I've seen came out a JM 625-8. It measured.49+, I left it in. The fired primers do look different, no doubt which pin it has.
When I was speaking of broken pins I wasn't referring to fractured tips. I was refering to the C&S pins I've seen which have to whole tip broken off thru the tip to body transition (radius). BROKEN not just fractured or chipped.
When I was speaking of broken pins I wasn't referring to fractured tips. I was refering to the C&S pins I've seen which have to whole tip broken off thru the tip to body transition (radius). BROKEN not just fractured or chipped.
Randy Lee
Member
Hi tomcatt51,
I too have seen such failures with non OEM pins.
It was in part one reason I had my own version made. Had there been two design changes in the C&S pins, I would probably not be selling and using my own.
Many would assume that making a firing pin is a simple task. For me, it took two full years of testing before I would release my parts to the general public. My prototype pins were installed and used by several shooters to see if any failures would occur in competition. One gentlemean has been documenting dry fire cycles without dummy rounds and at last count is up to 18,000. So far so good. My second generation competition only firing pins will be available sometime this year. I need to pay for my engineering degree somehow...
Most of my commentary was directed towards the factory Ti pins which I have seen fail.
I too have seen such failures with non OEM pins.
It was in part one reason I had my own version made. Had there been two design changes in the C&S pins, I would probably not be selling and using my own.
Many would assume that making a firing pin is a simple task. For me, it took two full years of testing before I would release my parts to the general public. My prototype pins were installed and used by several shooters to see if any failures would occur in competition. One gentlemean has been documenting dry fire cycles without dummy rounds and at last count is up to 18,000. So far so good. My second generation competition only firing pins will be available sometime this year. I need to pay for my engineering degree somehow...
Most of my commentary was directed towards the factory Ti pins which I have seen fail.
Randy Lee
Member
It's based upon observation of guns coming into the shop. Of the guns that were made in the last year, some of them had .49+ pins in them. So my guess is that they are mixed in with the inventory. You may have to talk to CS and ask for a longer than .483" pin as I have no part number for it.
nicky4968
Member
I am very late to this discussion. (It's post this or start on first transcripts of the year).
I bought a used 625 Mountain Gun. After several hundred rounds I realized the firing pin was broken. There had been no mis-fires. I told S&W of my problem and they sent me a new pin (and spring, which was thoughtful). Pistol runs fine now.
Take your pistol with the MIM frame-mounted pin. Point down toward the floor. Look through the frame at the rear of the cylinder. If you see the pin protruding, it is "broken", as mine was, but probably still functioning.
Had this happened with a hammer-mounted firing pin (which I've done), that's the end of it until you get it repaired.
Six of one and half a dozen of the other, as far as I'm concerned. But I was impressed that the two-piece pin functioned so well.
I bought a used 625 Mountain Gun. After several hundred rounds I realized the firing pin was broken. There had been no mis-fires. I told S&W of my problem and they sent me a new pin (and spring, which was thoughtful). Pistol runs fine now.
Take your pistol with the MIM frame-mounted pin. Point down toward the floor. Look through the frame at the rear of the cylinder. If you see the pin protruding, it is "broken", as mine was, but probably still functioning.
Had this happened with a hammer-mounted firing pin (which I've done), that's the end of it until you get it repaired.
Six of one and half a dozen of the other, as far as I'm concerned. But I was impressed that the two-piece pin functioned so well.
bountyhunter
Member
- Joined
- Jan 8, 2002
- Messages
- 1,862
- Reaction score
- 464
That's the ones I have heard so much about. The comp shooters threw them away and won't use them because they are so unreliable, but they say the factory pins are much better.
Schofieldkid81
Member
Hey Randy, I was searchin the net because I had recently had a pierced primer and noticed the firing pin had a chip on the tip. I found these posts and it describes exactly what has happened to me. My gun is a new 610-3 and it has the more conical shaped firing pin. I have a lew horton 24-6 that has the more spherical shaped firing pin, and it has at least 1,000 rounds with no problem.
Is you firing pin "extra length"?
Is you firing pin "extra length"?
tomcatt51
Member
Randy's pins are .500"-.501"
OP
Ultima-Ratio
Member
Ummmm? Which comp shooters Mr Bounty Hunter (ragwriter) and whom do I call first?
Bill@C&S or Jerry (a serious comp shooter)
It appears to me (a casual board reader)(and Guncrank who depended on C&S quality) that someone is denigrating C&S without documentation.
Bill@C&S or Jerry (a serious comp shooter)
It appears to me (a casual board reader)(and Guncrank who depended on C&S quality) that someone is denigrating C&S without documentation.
bountyhunter
Member
- Joined
- Jan 8, 2002
- Messages
- 1,862
- Reaction score
- 464
Try looking up the subject on the Brian Enos forum where the knowledge level exceeds what you could ever aspire to. Ask any of the revo comp shooters if they would ever use a C+S firing pin again.
And FYI: if you keep slinging the flame insults like "ragwriter", you are going to get your sorry ass banned and nobody will remember you were ever here. And we will say good riddance.
bountyhunter
Member
- Joined
- Jan 8, 2002
- Messages
- 1,862
- Reaction score
- 464
Show me where it says I have to educate the members of the short yellow bus club... but, since you are the one slinging the smart mouth accusations that I can't document what I say, I will waste the time to answer your post:
bountyhunter
Member
- Joined
- Jan 8, 2002
- Messages
- 1,862
- Reaction score
- 464
http://www.brianenos.com/forums/index.php?showtopic=56801&hl=C+S+firing+pin
Is that "documented" enough for you?
Is that "documented" enough for you?
bountyhunter
Member
- Joined
- Jan 8, 2002
- Messages
- 1,862
- Reaction score
- 464
As for "denigrating C+S", I only tell the truth about the firing pins that were poorly made for SW revolvers. Every one of the three I bought had to be fitted (shaved) to get them to work at all. They never broke because I pulled them and replaced them with the originals before they did.
I never said everything C+S makes is junk, I happen to have C+S sears and hammers in both my HI Powers. They are very good parts, but the SW replacement firing pins are not.
I never said everything C+S makes is junk, I happen to have C+S sears and hammers in both my HI Powers. They are very good parts, but the SW replacement firing pins are not.
Randy Lee
Member
Hi all,
It seems that there are several factors which are being discussed here regarding firing pins, pin design, breakage, misfires, chipping, etc.
Pin breakage is a fact of life. Any part can fail, but if you look at the raw numbers of guns out there the percentage of broken factory pins is well less than 1 percent- it just happens to suck when it's your pin that breaks. I disclosed that I have one documented failure of my pin design to date. In order to improve the performance and service life of my parts, I require honest input- so I encourage all my customers to keep me informed if their pin fails.
Failures to fire in factory sprung revolvers vs. competition platform revolvers. I have replaced roughly 100 factory short firing pins this past year in off duty j-frame revolvers because of failures to fire factory ammunition. My pin was designed to be slightly longer and work reliably with factory mainspring forces.
The competitive revolver is a very different beast. We use Federal primers pretty much exclusively, the hammers are often lightened to the point that they look like matchsticks. The mainspring forces are so light that only soft primers can be used. The quote used by Bountyhunter mentioning the misfires with my pin is from a thread on Brian Enos's forum which is devoted to the competition revolver and NOT a general purpose revolver. I encourage people to read the posts on that particular thread in its entirety.
My firing pin requires a bit of modification to improve function when trigger pulls are less than 5 lbs on the double action.
Most of the comp DA guns I ship out are between 4 and 4.75 lbs- but primers must be federal primers which are set to .008-.010 below the surface of the case head. With light hammers and in this weight range, primers will shift forwards in the primer pocket and dampen impact of the firing pin. My prototype light action revolver runs reliably with my handloads at just below 3 lbs on the double action. This is at the ragged edge of the operational envelope and uses my pin(albeit modified). A factory pin will not work in this case.
I have designed a new firing pin which is intended exclusively for competition revolvers which will improve ignition at the lighter weight pulls.
It seems that there are several factors which are being discussed here regarding firing pins, pin design, breakage, misfires, chipping, etc.
Pin breakage is a fact of life. Any part can fail, but if you look at the raw numbers of guns out there the percentage of broken factory pins is well less than 1 percent- it just happens to suck when it's your pin that breaks. I disclosed that I have one documented failure of my pin design to date. In order to improve the performance and service life of my parts, I require honest input- so I encourage all my customers to keep me informed if their pin fails.
Failures to fire in factory sprung revolvers vs. competition platform revolvers. I have replaced roughly 100 factory short firing pins this past year in off duty j-frame revolvers because of failures to fire factory ammunition. My pin was designed to be slightly longer and work reliably with factory mainspring forces.
The competitive revolver is a very different beast. We use Federal primers pretty much exclusively, the hammers are often lightened to the point that they look like matchsticks. The mainspring forces are so light that only soft primers can be used. The quote used by Bountyhunter mentioning the misfires with my pin is from a thread on Brian Enos's forum which is devoted to the competition revolver and NOT a general purpose revolver. I encourage people to read the posts on that particular thread in its entirety.
My firing pin requires a bit of modification to improve function when trigger pulls are less than 5 lbs on the double action.
Most of the comp DA guns I ship out are between 4 and 4.75 lbs- but primers must be federal primers which are set to .008-.010 below the surface of the case head. With light hammers and in this weight range, primers will shift forwards in the primer pocket and dampen impact of the firing pin. My prototype light action revolver runs reliably with my handloads at just below 3 lbs on the double action. This is at the ragged edge of the operational envelope and uses my pin(albeit modified). A factory pin will not work in this case.
I have designed a new firing pin which is intended exclusively for competition revolvers which will improve ignition at the lighter weight pulls.
