Firing pin keeps breaking

[rijndael]

I wonder if your replacement firing pins are a bad fit for the bushed hole, which is why the life is greatly reduced after the initial pin.

 

[Ggmac]

Suggestion , on your next pin install , take the stripped spring and insert it into the bolt and see if there’s resistance. Then with it still installed ( stripped ) and pushed through the bolt face as if fired , see if you can center the cocking piece end without pressure or bending . No coffee yet so I hope this makes sense.
Gary

 

[6.5 forever]

^^^^^^
Good advice.

 

[AlNyhus]

Only on my first cup of Sulawesi but my suspicion is an unsupported pin tip and/or an off center pin hole in the bolt face.
- Check the size of the pin hole in the bolt face with a pin gauge and compare it to the size of the pin tip. Make sure the hole is round and not peened out of round.
- Make sure the pin tip is fully supported when it's in the cocked position.
- When it's cocked, take a small flash light and look in the pin hole. You should see the pin tip centered in the hole.

I couldn't see this with my naked eye but a 10X loupe was pretty revealing.

Good shootin' -Al

 

[boltfluter]

I agree with Al, you have some type of alignment problem. Whenever I bush a firing pin hole, the last thing I do is what I call a drop test. As in, install the firing pin by itself, screw in the shroud, allow the pin to drop through it's normal range of motion. There should be no binding whatsoever. If there is, I figure out why, before it leaves the shop. As my process fully contains the firing pin through the full range of motion, I also check for correct pin protrusion as well. Sometimes a small radius in the wrong spot can make for a fun day! Not! Lol. Good luck.

Paul

 

[AlNyhus]

18trapper: I would strongly suggest having Paul (www.boltfluting.com) rehab your bolt and pin assy. This is something that unless you're set up to diagnose and fix the issue, it's almost impossible get a handle on.

Good shootin' -Al

 

[boltfluter]

If I were a betting man, my bet would be on a firing pin hole the is not centered and a dead sharp hole where the firing pin enters. Hope that makes sense. I always chamfer the back side of my bushing for this very reason. Dead sharp edges really like to grab at the most inopportune times!

Paul

 

[expiper]

could there be the remains of a "blanked" primer causing the miss-alignment and firing pin damage...Roger

 

[BoydAllen]

If it were mine, I would take the mirror off of my Teslong bore scope and take a look inside the bolt.

 

[FNSafari]

Ptg bolt says it all.

A freakin correct brother!!!!!!!!!

 

[Alex Wheeler]

It's probably pulling clear of the tunnel when cocked, losing it's guidance. Bushing it with a long enough bushing to keep guidance would probably be the solution. I want to say I've heard of this on those, now that you posted this.

Tom

This is another possibility. Look at the pin tip, if its pulling out it will have an angle forming on the tip from scraping into the hole. A better pic of the tip would help.
Some actions dont capture the front of the pin, Remington and Kelblys are examples. But they have a funnel to "catch" and guide the pin tip. Without that funnel the pin tip has to stay captured or you have serious problems.

 

[gunsandgunsmithing]

IDK, since you've been through multiple pins. A few years ago, Stiller had some pins that did not get proper heat treatment that looked a lot like yours..fwiw. Not sure if he was making the pins or buying them but they were std Remington pins minus the reduced tip diameter. I guess it's possible that there's a bad batch out there but seems very unlikely.

 

[J_idaho]

Only on my first cup of Sulawesi but my suspicion is an unsupported pin tip and/or an off center pin hole in the bolt face.
- Check the size of the pin hole in the bolt face with a pin gauge and compare it to the size of the pin tip. Make sure the hole is round and not peened out of round.
- Make sure the pin tip is fully supported when it's in the cocked position.
- When it's cocked, take a small flash light and look in the pin hole. You should see the pin tip centered in the hole.

I couldn't see this with my naked eye but a 10X loupe was pretty revealing.

Good shootin' -Al

So is it just mushroomed from 5000 rounds pounding on it???

 

[18trapper]

This is another possibility. Look at the pin tip, if its pulling out it will have an angle forming on the tip from scraping into the hole. A better pic of the tip would help.
Some actions dont capture the front of the pin, Remington and Kelblys are examples. But they have a funnel to "catch" and guide the pin tip. Without that funnel the pin tip has to stay captured or you have serious problems.

I took it to my gunsmith today and they swapped out the firing pin and also changed the piece that engages the sear(whatever that’s called). They are thinking it’s probably a bolt body issue but want me to try that and keep an eye on it and take it back if the pin issue reappears.

As a side note, I’ve been pulling out my hair over poor accuracy for awhile now that I couldn’t pin point. I was lucky to get 1.25 Moa groups along with unexplained flyers. After they fixed the bolt today we shot 10 rounds and it’s back to .5 to .75 moa. Hopefully it holds up

 

[WSnyder]

piece that engages the sear

cocking piece

 

[DShortt]

If it started after switching from the Timney that could be the answer depending on the vintage of the Timney. For quite some time the Timney’s sear was about .050” shorter than just about everyone else. This left it with much less to zero cock on close with a .050” shorter than everyone else pin fall. Mby the Timney trigger left the pin supported in the pin hole but with the TT it is not supported. Also with a PTG bolt who knows what you actually have inside it as far as dimensions go. As a side note PTG has made bolts that take two different style pins. The std and the BR. The BR takes a long pin nose very similar to what Greg Tannel does that is fully supported unlike the std and factory Rem bolts. A std pin will not fit in the PTG BR style bolt so that is not your issue, I just wanted to note there are anomalies out there.

I took it to my gunsmith today and they swapped out the firing pin and also changed the piece that engages the sear(whatever that’s called). They are thinking it’s probably a bolt body issue but want me to try that and keep an eye on it and take it back if the pin issue reappears.

As a side note, I’ve been pulling out my hair over poor accuracy for awhile now that I couldn’t pin point. I was lucky to get 1.25 Moa groups along with unexplained flyers. After they fixed the bolt today we shot 10 rounds and it’s back to .5 to .75 moa. Hopefully it holds up

So..... your 'smith doesn't have a scope to examine the inside of your bolt body?

Huh.

 

[18trapper]

So..... your 'smith doesn't have a scope to examine the inside of your bolt body?

Huh.

Yea he looked into it with a Hawkeye borescope but didn’t see anything that didn’t look normal

 

[BoydAllen]

I would blacken the pin, and spring, from tip to the front of the shroud, with a broad tipped marker. Reinstall it, and after a trip to the range take a look at where it wore off. Looking at the length that is the same diameter at the FP tip, I think that this bolt was designed to have the tip stay in its hole. If for some reason the pin was cocked to the point where the tip came out of the back of the hole, then things could possibly get bent, and once that happened.......

 

[18trapper]

I would blacken the pin, and spring, from tip to the front of the shroud, with a broad tipped marker. Reinstall it, and after a trip to the range take a look at where it wore off. Looking at the length that is the same diameter at the FP tip, I think that this bolt was designed to have the tip stay in its hole. If for some reason the pin was cocked to the point where the tip came out of the back of the hole, then things could possibly get bent, and once that happened.......

I will do that next week on Tuesday and report back.

 

[DShortt]

Yea he looked into it with a Hawkeye borescope but didn’t see anything that didn’t look normal

Ok. Good to know but something isn’t right or this wouldn't keep happening and there are only so many possibilities.

Start over from the beginning. As if you just started looking at it.

What did he set your pin protrusion at and don’t Google it for the correct figure.

This isn't rocket science. Something is WAY off somewhere or this wouldn't be happening. Even cheap rifles don't bend firing pins and make gouges like that.