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Extended vs Factory Firing Pin


AusPPC

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I know that an aftermarket extended FP is designed to improve ignition reliability.

But have any of you found that when returning to a stock factory FP that ignition reliability improved? Or that you could now go down in mainspring tension whilst maintaining ignition reliability?

I am running an Apex extended FP (plus Apex DA only hammer) in a smoothed, shimmed and blueprinted K-frame with zero endshake, and finding that my 100% ignition reliability floor is 7.5 pounds, and wondering if I might drop an extra pound by experimenting with a factory firing pin?

All primers are Federal seated several thou' below flush.

Cheers :)

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Normally the deep seated primers is one of the items that calls for an extended firing pin. The best way to answer your question is to simply switch firing pins and see what happens. One thing I can think of to check is that the bottom of the hammer is not contacting the rebound slide when the hammer is all the way down. Sometimes after adding a trigger stop the rebound slide doesn't go back far enough to clear the hammer. When the hammer hits the rebound slide just before it contacts the frame, the rebound slide and spring act as a shock absorber and cushion the blow of the hammer to the firing pin.

With that setup you should be getting between 5 and 6 pound 100%.

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Normally the deep seated primers is one of the items that calls for an extended firing pin. The best way to answer your question is to simply switch firing pins and see what happens. One thing I can think of to check is that the bottom of the hammer is not contacting the rebound slide when the hammer is all the way down. Sometimes after adding a trigger stop the rebound slide doesn't go back far enough to clear the hammer. When the hammer hits the rebound slide just before it contacts the frame, the rebound slide and spring act as a shock absorber and cushion the blow of the hammer to the firing pin.

With that setup you should be getting between 5 and 6 pound 100%.

Toolguy, you know I checked everything I could think of that might foul the hammer - except that! :)

Thanks for the tip, I will definitely check that as I have had a trigger stop installed and being a PPC gun I run the trigger quite slowly, so its possible the rebound slide isn't getting out of the way of the hammer foot in time.

Right now if I run 6.5 pounds I get a 2% light strike rate, but at 7.5 pounds I get 0%.

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I know that an aftermarket extended FP is designed to improve ignition reliability.

But have any of you found that when returning to a stock factory FP that ignition reliability improved?

Depends on what you mean by "stock". SW made some bad pins that were too short and those may give worse ignition. SW has made proper length pins in both steel and titanium, so the Ti pins may give a shade better ignition because of reduced mass which gives higher velocity and a bit more strike energy. In general, I doubt very much you will see any significant difference between aftermarket extended pins and GOOD (proper length) stock pins. I didn't and I specifically tested for it. But I was using factory ammo, not reloads and stock hammer and trigger.

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How heavy a rebound spring are you running ?

Not sure actually, it is what my gunsmith fitted during the build. I do know that it has had a couple of coils clipped from it, and the rebound pressure is quite light, but never sluggish and has never hung up even when released slowly, thanks to extensive honing and polishing of all contact surfaces.

By my evaluation, even for a PPC gun, I would not want to go much lower from where it is now as it seems to be optimal.

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I know that an aftermarket extended FP is designed to improve ignition reliability.

But have any of you found that when returning to a stock factory FP that ignition reliability improved?

Depends on what you mean by "stock". SW made some bad pins that were too short and those may give worse ignition. SW has made proper length pins in both steel and titanium, so the Ti pins may give a shade better ignition because of reduced mass which gives higher velocity and a bit more strike energy. In general, I doubt very much you will see any significant difference between aftermarket extended pins and GOOD (proper length) stock pins. I didn't and I specifically tested for it. But I was using factory ammo, not reloads and stock hammer and trigger.

Thanks, this is useful feedback. So by those results, even with a good (0.495") length factory pin, I would not be improving from the Apex competition pin. I guess the only real difference is that the Apex comp FP uses a pointed tip, whereas the factory uses a dome. But essentially, if I'm looking for improved ignition (especially on below-flush primers) I'm unlikely to find it in a factory pin. Cheers :)

I guess what I am really looking for is something I've overlooked that might be soaking up a little of the strike energy, enabling me to drop some mainspring weight. Everything looks and feels good, but I haven't checked the hammer foot / rebound seat as per Toolguys recommendation, so that seems to be the next avenue to explore. This actually makes some sense, given that ('a') I'm running a factory trigger with an aftermarket Apex hammer that would not have been "mated" to each other at the factory, and ('b') I'm running a trigger stop via a setscrew in the trigger guard.

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I know that an aftermarket extended FP is designed to improve ignition reliability.

But have any of you found that when returning to a stock factory FP that ignition reliability improved?

Depends on what you mean by "stock". SW made some bad pins that were too short and those may give worse ignition. SW has made proper length pins in both steel and titanium, so the Ti pins may give a shade better ignition because of reduced mass which gives higher velocity and a bit more strike energy. In general, I doubt very much you will see any significant difference between aftermarket extended pins and GOOD (proper length) stock pins. I didn't and I specifically tested for it. But I was using factory ammo, not reloads and stock hammer and trigger.

Thanks, this is useful feedback. So by those results, even with a good (0.495") length factory pin, I would not be improving from the Apex competition pin.

That seems to be disputed depending on who you ask. When the extended FP's first came out a long time ago, I tested them on the three model 66 guns I used for comp shooting. I used factory ammo and stock parts with actions lightened by polishing and reduced springs. I reduced mainspring force until I got DA misfires and accurately measured the DA pull weight using both stock pins and extended. There was no difference in performance, but I left the long pins in anyway since I had paid good money for them. Two of them broke rather soon and I chucked the third one and that was the end of extended firing pins for me.

There have been posters who claim the extended pins "improved" ignition and maybe they did (in their case).

AFAIK, if the pin is correct length (which I think is .495) and there are no underlying issues like excessive end shake, excessive cylinder breech gap, etc, the stock pins work just as well.

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I know that an aftermarket extended FP is designed to improve ignition reliability.

But have any of you found that when returning to a stock factory FP that ignition reliability improved?

Depends on what you mean by "stock". SW made some bad pins that were too short and those may give worse ignition. SW has made proper length pins in both steel and titanium, so the Ti pins may give a shade better ignition because of reduced mass which gives higher velocity and a bit more strike energy. In general, I doubt very much you will see any significant difference between aftermarket extended pins and GOOD (proper length) stock pins. I didn't and I specifically tested for it. But I was using factory ammo, not reloads and stock hammer and trigger.

I guess what I am really looking for is something I've overlooked that might be soaking up a little of the strike energy, enabling me to drop some mainspring weight.

Everybody looks for that. The only items I recall regularly doing that are:

1) Primers not fully seated on reloads.

2) End shake on the cylinder which allows it to move when struck.

As for:

I guess the only real difference is that the Apex comp FP uses a pointed tip, whereas the factory uses a dome.

I don't know it that increases ignition or not. It didn't for me, but they were C+S extended pins. The ends were conical as opposed to round on the stock pins.

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I know that an aftermarket extended FP is designed to improve ignition reliability.

But have any of you found that when returning to a stock factory FP that ignition reliability improved?

Depends on what you mean by "stock". SW made some bad pins that were too short and those may give worse ignition. SW has made proper length pins in both steel and titanium, so the Ti pins may give a shade better ignition because of reduced mass which gives higher velocity and a bit more strike energy. In general, I doubt very much you will see any significant difference between aftermarket extended pins and GOOD (proper length) stock pins. I didn't and I specifically tested for it. But I was using factory ammo, not reloads and stock hammer and trigger.

Thanks, this is useful feedback. So by those results, even with a good (0.495") length factory pin, I would not be improving from the Apex competition pin.

That seems to be disputed depending on who you ask. When the extended FP's first came out a long time ago, I tested them on the three model 66 guns I used for comp shooting. I used factory ammo and stock parts with actions lightened by polishing and reduced springs. I reduced mainspring force until I got DA misfires and accurately measured the DA pull weight using both stock pins and extended. There was no difference in performance, but I left the long pins in anyway since I had paid good money for them. Two of them broke rather soon and I chucked the third one and that was the end of extended firing pins for me.

There have been posters who claim the extended pins "improved" ignition and maybe they did (in their case).

AFAIK, if the pin is correct length (which I think is .495) and there are no underlying issues like excessive end shake, excessive cylinder breech gap, etc, the stock pins work just as well.

Indeed. My research so far seems to indicate that it is rare for an extended FP to worsen ignition reliability, all else remaining equal.

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I know that an aftermarket extended FP is designed to improve ignition reliability.

But have any of you found that when returning to a stock factory FP that ignition reliability improved?

Depends on what you mean by "stock". SW made some bad pins that were too short and those may give worse ignition. SW has made proper length pins in both steel and titanium, so the Ti pins may give a shade better ignition because of reduced mass which gives higher velocity and a bit more strike energy. In general, I doubt very much you will see any significant difference between aftermarket extended pins and GOOD (proper length) stock pins. I didn't and I specifically tested for it. But I was using factory ammo, not reloads and stock hammer and trigger.

I guess what I am really looking for is something I've overlooked that might be soaking up a little of the strike energy, enabling me to drop some mainspring weight.

Everybody looks for that. The only items I recall regularly doing that are:

1) Primers not fully seated on reloads.

2) End shake on the cylinder which allows it to move when struck.

As for:

I guess the only real difference is that the Apex comp FP uses a pointed tip, whereas the factory uses a dome.

I don't know it that increases ignition or not. It didn't for me, but they were C+S extended pins. The ends were conical as opposed to round on the stock pins.

I have extended the seating punch on my press (LNL-AP) and seat primers with it with impunity, so I can only assume they are seated firmly. But I guess there is a reason some use hand priming, though I really can't imagine using any more pressure than what my press delivers with all its leverage.

As example, I can see a slight dimple in the centre of the Federals which is the anvil pressing up against the cup - does that typically indicate sufficient seating depth?

In regards to end-shake, there is absolutely none on the revolver in question. The whole action has been blueprinted and is tight, as evidenced by the X-ring grouping at 50 yards, so I've ruled out that as a problem. I've installed shims on both the trigger and hammer, and have confirmed the hammer is striking centrally without contact to the frame, and also that the firing pin is protruding sufficiently. Hence my confusion and blaming the firing pin.

The variables left to check would be hammer foot / rebound seat interference, and firing pin binding. I'll be sure to report back once I've checked these.

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"slight dimple in the centre of the Federals" Bingo. This could be the root of your issues.

When you are setting the primers that hard the anvil is cracking the cake / disk of priming compound. This then moves away from the anvil so you either have to strike it with more force or multiple time for it to ignite.

Had a fellow club member have the same issue with his Service / Unrestricted gun. The gun was apart many times and our Gunsmith could find an issue. Changed the way he was seating his primes and issues went away.

His process now is to gently push the press lever till he feels the primer has hit the bottom, rotate the case 180 degrees and presses the lever again. This ensures that the primer sits squarely in the primer pocket. He is using a Dillon 650.

I have been told this by a few other shooters. Yes this is a slow and long winded process but there is nothing worse then going to an open and having a light strike and dropping 10 points.

The way I do it is once I feel that the primer has hit the bottom I add a smidge more pressure. If you do a little at a time and look at the primer each step you will see the radius at the edge of the primer flatten out. Once you see it start to flatten then that the depth to set your press / primer stop. Any further and it is too much. Just hope that you don't have any deep primer pockets.One of the advantages of hand priming is that you feel the seating pressure go up exponentially with you hit the bottom of the primer pocket. I keep thinking about using one of those primer pocket reamers to make sure all my primer pocket depths are the same.

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"slight dimple in the centre of the Federals" Bingo. This could be the root of your issues.

When you are setting the primers that hard the anvil is cracking the cake / disk of priming compound. This then moves away from the anvil so you either have to strike it with more force or multiple time for it to ignite.

Had a fellow club member have the same issue with his Service / Unrestricted gun. The gun was apart many times and our Gunsmith could find an issue. Changed the way he was seating his primes and issues went away.

His process now is to gently push the press lever till he feels the primer has hit the bottom, rotate the case 180 degrees and presses the lever again. This ensures that the primer sits squarely in the primer pocket. He is using a Dillon 650.

I have been told this by a few other shooters. Yes this is a slow and long winded process but there is nothing worse then going to an open and having a light strike and dropping 10 points.

The way I do it is once I feel that the primer has hit the bottom I add a smidge more pressure. If you do a little at a time and look at the primer each step you will see the radius at the edge of the primer flatten out. Once you see it start to flatten then that the depth to set your press / primer stop. Any further and it is too much. Just hope that you don't have any deep primer pockets.One of the advantages of hand priming is that you feel the seating pressure go up exponentially with you hit the bottom of the primer pocket. I keep thinking about using one of those primer pocket reamers to make sure all my primer pocket depths are the same.

That's a pretty interesting observation. I compete at a lot of Service / 1500 opens driving long distance and forking out for a hotel when I do, so a 'clicker' would really ruin my weekend which is why with this new revolver I'm working through everything to maintain a reliable 100% ignition rate.

I've heard elsewhere about the 'cracked pellet' theory, which seems to make sense given if the anvil is denting the cup it has to be putting a lot of pressure on the pellet. My press setup has no depth setting, and I've extended the punch length such that it will keep seating until the primer is totally bottomed out, or I stop pushing. Hence why I routinely get the dimples.

I'll have to load a session using your technique and give it a go Cheers :)

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AusPPC, out of curiosity have you checked the cartridge headspace with the brand of brass that you are using? Do you use mixed brass or all one brand/batch? Do you clean primer pockets? Do you ream them or use a primer pocket uniformer?

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I found 2 f100 primers in the last flat I used that had either an anvil reversed or cocked in the cup.

I always check for issues when using the flip tray. The one cocked actually showed up as rounded cup that first caught my eye.

Don't know if they were trying to kick more out and reduced their QC or what.

I've had more problems with the pointed fp's than the regular nose.

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AusPPC, out of curiosity have you checked the cartridge headspace with the brand of brass that you are using? Do you use mixed brass or all one brand/batch? Do you clean primer pockets? Do you ream them or use a primer pocket uniformer?

I use Starline brass, so primer pockets are consistent, though I don't apply any uniforming (reaming / swaging) process as the Starlines are factory beveled and run through the press quite nicely.

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I found 2 f100 primers in the last flat I used that had either an anvil reversed or cocked in the cup.

I always check for issues when using the flip tray. The one cocked actually showed up as rounded cup that first caught my eye.

Don't know if they were trying to kick more out and reduced their QC or what.

I've had more problems with the pointed fp's than the regular nose.

It's my wife's job to fill all the primer tubes while I'm at work, so I never get to see the anvils haha. Might be worth checking, though I note the 'clicker' rate at my lowest strain screw setting is pretty consistent at 2% across batches.

Interesting you've had problems with the pointed FP's moreso than the rounded. If the pellet is being cracked by seating pressure, then it's possible a rounded pin would distribute the blow more widely across the pellet and improve ignition.

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How long have Apex been making hammers for K frames? Can't find them listed anywhere on their website? Are you sure you have a K frame hammer?

L and K frame use the same hammer. It will say L frame in the title but in the details you will see k\L frame.

https://store.apextactical.com/WebDirect/Products/Details/191686

That's correct, I definitely have an Apex hammer in my K-frame, the website is just a bit cryptic with the descriptions..

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I had a 625 and felt I needed an extended FP for better ignition, so I ordered a C&S unit, I started getting pierced primers. I re installed the factory unit.

I had measured the 2 (forget what the measurements were) and found that after Apex had released theirs, that the Apex was in between the factory and the C&S.

I would suggest that the Apex one would be all that's required.

YMMV.

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Upon further inspection (despite earlier checks), it appears I am still getting frame rubbing on the left side of the hammer, as evidenced by abrasion on both the hammer and hammer window.

I've now altered the order of the shims (1 x Left & 2 x Right) and relieved the hammer window slightly with a diamond file, and the hammer is striking centrally without fouling any part of the frame. I will monitor for any abrasion which should be easy to detect given the hammer is polished bright.

I also checked the firing pin, firing pin spring and firing pin channel and all are clean and unobstructed (a pipe cleaner was useful here).

Lastly, as per Toolguy's suggestion, I checked for interference between the hammer foot and rebound seat, and at the full hammer-forward position found there was a clear gap between the two, so no fouling or cushioning occurring there.

In short, the only problem re: ignition is frame rubbing, so I think I found the culprit :) Thank you to everyone for their input.

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