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Thread: Broken firing pin

  1. #11
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    From the original post, it looks to be welded. Failure due to fatigue, spot friction weld?

    I'd be content with 10k+ rounds with this pin.

  2. #12
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    Are the deminsions different from 5.56x45mm firing pins? And what are the expected life span of firing pins? Both Newb questions, so forgive my ignorance. Just trying to gain a little knowlege from your failure.
    Honesty, Honor, and Integrity Are Everything!

  3. #13
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    Probably not a friction weld which properly done is very reliable but the equipment is expensive. Probably a stud weld. A firing pin should last almost forever and when it does fail it should be because the tip wore out.

    The 5.45 pins are identical as far as I can tell to the 5.56 pins. Expected life of a firing pin? 50K? 100K? A lot more than 10K I think.
    Last edited by Suwannee Tim; 02-15-13 at 21:25.

  4. #14
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    How are firing pins generally manufactured?

  5. #15
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    If stud weld, typical failure right above welded joint.
    Last edited by rdbse; 02-15-13 at 22:33.

  6. #16
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    Quote Originally Posted by MK18Pilot View Post
    I would bet against that firing being a two piece welded design. I have never seen one break like that though.
    Me too. I wouldn't even know where to buy a welded FP (if it is true).


    OP, were you using the stiffer red hammer spring??




    C4
    Last edited by C4IGrant; 02-15-13 at 22:01.

  7. #17
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    Quote Originally Posted by MK18Pilot View Post
    I would bet against that firing being a two piece welded design. I have never seen one break like that though.
    If a firing pin were to break anywhere but the tip it would break at that spot. It is the end of the smallest radius fillet and gets the worst abuse of hot gas, and in a 5.45 would be impacted by corrosive salts. A small imperfection propagated through the hardened layer and led to a rapid failure of the shaft.
    Sweat saves blood, blood saves lives, but brains saves both.

  8. #18
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    Send those pictures or the firing pin itself to S&W and see what they can come up with. I'm sure their technical staff would appreciate feedback especially in reference to failures.
    Last edited by 3 AE; 02-15-13 at 23:21.

  9. #19
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    It wouldn't make sense to weld a firing pin - they must be turned from a solid rod.

  10. #20
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    Quote Originally Posted by rojocorsa View Post
    How are firing pins generally manufactured?
    An educated guess on my part, firing pins are turned from bar stock on an automatic screw machine.

    Quote Originally Posted by C4IGrant View Post
    Me too. I wouldn't even know where to buy a welded FP (if it is true).
    OP, were you using the stiffer red hammer spring??
    C4
    I am using the standard hammer spring now. My extra power spring broke at about 7K rounds and I put the original spring back. As far as knowing where to buy a welded pin, you may already have bought some. When some "entrepreneur" starts making some bogus item the items sometimes get into the legitimate supply chain before folks get wise. I have read of several incidents where counterfeit items got into legitimate supply chains, it's happened with pharmaceuticals, aircraft parts, electronic components and medical devices. It is a big worry in some circles.

    Quote Originally Posted by Shao View Post
    It wouldn't make sense to weld a firing pin - they must be turned from a solid rod.
    It makes a lot of sense if you are making a lot of pins. You would save a lot of turning time on the automatic screw machine. A LOT of time, depending on the screw machine and the setup you could cut turning time from several minutes to maybe half a minute. With a proper fixture welding the parts together would be trivial. I'm having a hard time persuading you folks that this pin is welded but I am very confident of it. I have two pins that show evidence of welding, the broken pin with a heat affected zone and inclusions and the intact pin with plating failure right on the heat affected zone. If I am right and someone is making bogus welded firing pins I predict we are going to see a lot more failures like this.

    Grant, have you ever seen a failure like this?
    Last edited by Suwannee Tim; 02-16-13 at 08:03.

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