Possible causes for indented firing pin face?

[5.56 Bonded SP]

I have a rifle that has a firing pin with the tip of it being slightly cratered/indented, it has a firing pin spring as well ( not an AR15 ).
I am wondering what are the most common reasons for this. Is it possible that some of my reloads were headspaced a little too short, or is this a common wear indication seen with high round counts? I used a headspace gauge for the brass headspacing, it is the kind where you drop the brass into it like this device, I am wondering if maybe the headspace guage is slightly out of spec, it is for 223 not 308 https://ads.midwayusa.com/product/880646/le-wilson-case-length-headspace-gauge-308-winchester?utm_medium=shopping&utm_source=google&utm_campaign=Reloading+-+Metallic+Reloading+Equipment+(Not+Presses)&utm_content=880646&cm_mmc=pf_ci_google-_-Reloading+-+Metallic+Reloading+Equipment+(Not+Presses)-_-L.E.+Wilson-_-880646&gclid=EAIaIQobChMImfKHusCr1wIVUGB-Ch2TegOtEAQYAyABEgIatPD_BwE
I did find it strange because I have shot all the same reloads out of my AR15s, and none of my AR firing pins have the same crater on the face of the firing pin. As well, none of the reloads showed any over pressure signs that I was aware of, no flattened, blown, or pierced primers.

[ghostly]

Could you post a picture?

Is it a ring shape around the firing pin hole?


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[markm]

If the tip of the firing pin is etched, it's likely the result of pierced primers. It will typically get worse as a non-smooth firing pin will progressively pierce more primers... snowballing the problem until bolt face damage occurs.

[bigedp51]

If you can adjust firing pin protrusion the tip of the firing pin can be stoned and reshaped back to normal.

Many of my old milsurp rifles had the tip of the firing pitted from leaking primers at the center of the primer dent, and could be stoned/sanded and reshaped like new.

[5.56 Bonded SP]

Well, none of the primers of my fired brass have been pierced. I was wondering if maybe the soulder/headspace was bumped back too short? It is the tip of the firing pin. I pick up and inspect all my brass to be reloaded again, and there hasn't been a single pierced primer.

Also @ghostly, I don't think my camera phone will be able to take a decent picture. The bolt face looks fine, it's just the tip of the firing pin that is slightly cratered, the gun has probably 3000-5000 rounds though it, mostly factory ammo and about 500-1000 reloads.

[markm]

You have all of the fired cases accounted for? Is it a gun that's hard to get a replacement?

[TomMcC]

Well, if it's not pierced primers ( I agree with markm that this is usually the cause) then it has to be a substandard FP. Primer cups are way softer than a chrome plated steel pin. I can't envision how headspacing would erode the tip of a FP. Short headspacing might lead to bolt locking issues, at least that's how it seems to me, but eroded FP tips? I don't see that.

[5.56 Bonded SP]

You have all of the fired cases accounted for? Is it a gun that's hard to get a replacement?

Yes, I would say at least 95+% of fired brass has been accounted for, and I have not noticed any problems with the brass/primers. Some of the reloads were pretty hot, but of the hot reloads I checked all the primers and did not notice any abnormalities.
A new firing pin should only cost about 20 bucks, so it isn't a big deal getting a replacement, I just wanted to try and figure out a possible cause for this issue so that it isn't something that keeps happening. I figure I will just replace the extractor and stuff since the gun has had a lot of rounds through it.
The firing pin is not chrome lined, I think it has some type of nitride treatment.

The crater is pretty small, and I haven't noticed it getting bigger in the past few hundred rounds.

The gun is a Tavor X95 and here is the firing pin replacement on their site. https://iwi.us/product/tavor-firing-pin-with-firing-pin-spring/

[TomMcC]

Yes, I would say at least 95+% of fired brass has been accounted for, and I have not noticed any problems with the brass/primers. Some of the reloads were pretty hot, but of the hot reloads I checked all the primers and did not notice any abnormalities.
A new firing pin should only cost about 20 bucks, so it isn't a big deal getting a replacement, I just wanted to try and figure out a possible cause for this issue so that it isn't something that keeps happening. I figure I will just replace the extractor and stuff since the gun has had a lot of rounds through it.
The firing pin is not chrome lined, I think it has some type of nitride treatment.

The crater is pretty small, and I haven't noticed it getting bigger in the past few hundred rounds.

The gun is a Tavor X95 and here is the firing pin replacement on their site. https://iwi.us/product/tavor-firing-pin-with-firing-pin-spring/

Have you fired this same ammo in another of your guns? Any probs show up?

[5.56 Bonded SP]

Have you fired this same ammo in another of your guns? Any probs show up?

Yes I have, and no problems that I am aware of in other guns.

[markm]

It really only takes one pierced primer to damage a firing pin. It's still possible that's the cause. We just went through this with one of my ARs. Mine had gotten out of control however... some bolt face damage started to occur.

[5.56 Bonded SP]

It really only takes one pierced primer to damage a firing pin. It's still possible that's the cause. We just went through this with one of my ARs. Mine had gotten out of control however... some bolt face damage started to occur.

I suppose I am going to assume that is what happened. I never saw any pierced primers, but I guess this is the most likely culprit for my damaged firing pin.

I had a non AR type rifle years ago that used to pierce primers on factory ammo due to bad headspace, but I assume that can only happen if the bolt is not headspaced properly and would not happen if the shoulder of reloads were too short.

Could a possible cause for my recent damaged firing pin be that maybe one of my primers was not seated properly, which could of caused the firing pin to puncture the primer?

[markm]

but I assume that can only happen if the bolt is not headspaced properly and would not happen if the shoulder of reloads were too short.

It's likely more of a firing pin protrusion issue. The FP should only be allowed to protrude so much... even if the head space is wrong. I suppose there could be some gun designs where the FP depth/movement relied on correct head space...



Could a possible cause for my recent damaged firing pin be that maybe one of my primers was not seated properly, which could of caused the firing pin to puncture the primer?

I don't think so. I've had some high seated primers in bolt gun ammo over the years and never saw any issues. I think I've heard of slam fire from high primers, but not piercing. It's usually a hot round or a FP protrusion issue that gets this started.

[5.56 Bonded SP]

I don't think so. I've had some high seated primers in bolt gun ammo over the years and never saw any issues. I think I've heard of slam fire from high primers, but not piercing. It's usually a hot round or a FP protrusion issue that gets this started.

Interesting, I will take your word for it. I am just surprised as I have never gone past max load data, even though I am very anal and careful about my loads it is possible I made a mistake somewhere. That makes sense as well, you are right, a proper firing pin should not protrude far enough to pierce a primer even if the primer was not seated all the way.



It's likely more of a firing pin protrusion issue. The FP should only be allowed to protrude so much... even if the head space is wrong. I suppose there could be some gun designs where the FP depth/movement relied on correct head space...

That gun was such a POS, I don't know the answer to that for sure, all I know is that I had to have a gunsmith do a lot of work on it, and it had out of spec headspace. It is possible the firing pin was worked on as well.