Light hammer strike problem.....

Discussion in 'Handguns: Revolvers' started by km101, Nov 15, 2017.

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  1. Pudge

    Pudge Member

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    I am genuinely curious why the firing pin could be the correct length for single action, but too short for double action. Why would the physical dimensions of the firing pin be inadequate in one scenario, but functional an another?
     
  2. RugRev

    RugRev Member

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    It isn't the firing pin per se. In single action the hammer has a greater arc which compresses the mainspring more and thus hits faster with more force than in double action which would cause the firing pin to move forward more.
     
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  3. RealGun

    RealGun Member

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    I was wondering what the misfire primers look like and if, somehow, the primers are below flush, moving the goal posts as it were.
     
  4. 243winxb

    243winxb Member

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    A test for a Smith and Wesson revolver, model 28, 357mag., may work on other guns also<> Gun empty.
    Dryfire gun and hold trigger fully to rear.
    Cock hammer with thumb.
    Hook a weight around the hammer (for example 3 1/2 LB minimum weight for 357).
    The hammer must not move rearward when the gun is lifted.
    The hammer should lift 3 1/2 lbs without going into the cocked position.
     
  5. Pudge

    Pudge Member

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    So, it isn't an issue with the actual firing pin's dimensions, it is an energy transfer issue. A longer firing pin then might well address the symptom of the problem, but wouldn't actually fix the problem.
     
  6. RugRev

    RugRev Member

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    As noted by others the gun worked until it was disassembled. At that point in time the firing pin was adequate. Now, it isn't. So, something is hampering this transfer of energy to the firing pin or something happened with endshake and/or headspace that made ignition more difficult. Somehow, upon reassembly friction was increased in the firing mechanism or something put back in an incorrect manner. Somewhere on the 'net and I don't know how true this is a comment was made that the firing pins had a near minimal protrusion to allow passing the California Drop Test. If this be the case perhaps that is why the spring pressure is high on the gun. The firing pin is inertial so the harder the hammer hits it the further it will protrude unless it hits the end of its travel. Perhaps, somehow, the firing pin spring was damaged is another thought.
     
  7. SC Shooter

    SC Shooter Member

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    I had a similar problem with a S&W 686 when shooting hand loads. Factory loads were fine, so I reloaded some with a softer primer (I was originally using CCI primers) and voila!, Issue resolved.
     
  8. Zendude

    Zendude Member

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    How many rounds were fired in the gun prior to the spring swap? Was it enough to determine if the light strike issue is a new problem that only started after the spring swap?
     
  9. RealGun

    RealGun Member

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    That didn't fix the gun though.
     
  10. km101

    km101 Member

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    I fired around 350 - 400 rounds of .44 spl. rounds and 150 .44 magnum rounds with no light strikes. I changed the mainspring and started getting light strikes, changed back and the problem persisted.

    I sent the gun (S&W model 69 2.75") back to S&W and it has not been returned as of today. 12-23-17
     
    Last edited: Dec 23, 2017
  11. 460Shooter

    460Shooter Member

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    I had this exact issue with a performance center 686. It wouldn't reliably fire in double action. S&W put a longer firing pin in it as a fix. It works as it should now, but I have misgivings about the durability of that "repair".

    Time will tell.
     
  12. Pudge

    Pudge Member

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    When I think about it, it's weird. If a longer fp just masks the problem and only addresses the symptoms without repairing the problem, if the gun had been shipped with a longer fp initially and never exhibited the symptom of light strikes, would there have been a problem?
     
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  13. straightshooterjake

    straightshooterjake Member

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    Do you have the opportunity to measure the new firing pin? I am really curious whether it is an extra long firing pin, or whether it is just at the maximum standard spec.

    I believe that the nominal length for S&W frame mounted firing pins is .495. Most current firing pins are close to this length, but there have occasionally been some that are a bit short. My cut off is .492. If I find one shorter than that I replace it with a stock S&W pin that is up to correct spec. If I could not get a S&W pin that was within a couple thousands of .495, then I would use a standard length pin from another brand. Most extra length pins are around .510, and I personally would be cautious about using one in a duty gun. I have not heard of any extra length pins from S&W, though I could be wrong.

    Some years ago, the standard pins from S&W were shorter, sometimes .485 or less. Most guns with strong factory springs worked OK with these pins, but they really are a bit short. If I see one, I will replace it.

    This information about firing pins, as well as lots more info about trigger tuning and the causes of light strikes, can be found in my article which is referenced in post #5 of this thread.
     
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  14. Pudge

    Pudge Member

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    Was interested in this because I was dealing with a similar issue. Shims on the hammer and cylinder seem to have cleared it up for me.
     
  15. km101

    km101 Member

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  16. km101

    km101 Member

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    Got the gun back from S&W today! Only a two month turnaround!

    S&W says the problem was a broken firing pin! I did not think to measure the pin before I sent it off. New pin measures .496 ,so I guess it is a standard pin.

    PARTS REPLACED:
    Hammer.....stock, I never touched it.
    Mainspring.....stock, ". "
    Firing pin
    Trigger return spring.....was a Wolff 13# spring.
    Rebound slide......I had polished the contact surfaces.
    Firing pin spring......stock.

    No parts were returned, so I don't know the length of the broken pin. The only conclusion I can make is that the FP must have broken about the time of the spring swap, causing the light strikes that I blamed on the spring.
    They DID NOT correct the 15# plus double action pull as I requested. No mention of it in the paperwork.

    I will take it to the range this weekend to verify that the problem is corrected. Range report next week!
     
  17. 9mmepiphany

    9mmepiphany Moderator Staff Member

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    They usually won't touch it if it is within factory spec.

    If you had requested that the action be tuned, that would have gone through the Performance Center...and required a completely different workorder to be completed
     
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  18. km101

    km101 Member

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    Does anyone know what the factory spec is on a double action trigger pull? Seems to me that I have seen several comments about heavy trigger pulls on model 69's, so it must be pretty high.
     
  19. RugRev

    RugRev Member

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    I don't know about specs but John Taffin tested one recently in a gun magazine article on it and a Model 66 new and the double action was 14 pounds. And I thought Rugers had heavy pulls out of the factory.
     
  20. km101

    km101 Member

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    Ok, I finally got to the range to test fire my model 69 after its return from the factory. I'm moving so it took longer than expected.

    I fired 150 rounds total, 100 rounds of .44 special handloads and 50 rounds of factory .44 magnum with no misfires or light hammer strikes. All went "bang" as expected. Accuracy was good at 15 and 25 yards, and should improve as I get accustomed to the trigger, or have an action job done.

    Don't know why they changed out the stock parts unless it was just caution on the part of the 'smith who worked on it, but it is working fine now.

    I will not be using this gun for EDC until I have put more rounds through it and I feel comfortable that the problem is fixed. That will be about another 200 - 300 rounds without incident.
     
  21. RealGun

    RealGun Member

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    200-300 rounds of 44 is worth a lot of money. I would have just taken the shortcut directly to my gunsmith, if an action job was projected anyway.
     
  22. km101

    km101 Member

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    The model 69 is a fun gun to shoot and I can burn through lots of practice ammunition without trying. I reload most of my practice ammo, so it's not that expensive. And if the trigger improves I won't have to do an action job.
     
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