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Thread: Broken firing pin

  1. #61
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    When I had my knees in the breeze and ass in the grass we had a saying. Never forget that your rifle and other equipment was made by the lowest bidder. Mil Spec is not the end all. Even Mil Spec shit breaks.
    Train 2 Win

  2. #62
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    Quote Originally Posted by Shao View Post
    29 years of shooting and I've only seen broken firing pins on a couple of revolvers.

    EDIT: For anyone interested: A Ruger SP-101 and some POS Taurus
    Only one broken firing pin in 50 years of shooting for me. A Star PD 45ACP, the tip broke off.
    US Army 1966-69, VFW Life Member, Retired Geek

  3. #63
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    Eastern bloc ammo usually will have a harder primer than American ammo. Maybe this is the cause?

  4. #64
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    I've ran russian ammo in my S&W MP for 3000rds+ never had an issue...still shot two inch groups at 100yrds...I doubt its that...but never say never
    Last edited by thehun; 02-20-13 at 00:07.

  5. #65
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    I know that 7.62x39 made by Remington or Winchester isn't recommended for the sks because of slam-fires. That's due to the softer primers. That's how I came to my theory anyways.

  6. #66
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    Quote Originally Posted by thehun View Post
    I've ran russian ammo in my S&W MP for 3000rds+ never had an issue...still shot two inch groups at 100yrds...I doubt its that...but never say never
    The hardness of the primer cup has nothing to do with accuracy. It is also not limited to eastern bloc ammo, most military ammo has harder cups.

  7. #67
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    Quote Originally Posted by !Nvasi0n View Post
    I work in a metrology and metallurgy lab, as a quality control engineer...I can put this welded or not argument to bed in about 15 minutes if you wish. Let me know. You could ship it to me, and I could examine it after a metallographic mount and polish... Then etch it for weld flow in the appropriate acid for material type (probably picric). Then throw it under our stereoscope at 100-1000x to check for weld flow or the absence thereof.

    I'm with everyone else, pretty well sure it ain't welded.
    PM me your address and I'll get it in the mail. You guys have almost convinced me that it isn't welded. Wouldn't be the first time I was wrong.

  8. #68
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    I agree with Melon. Moral of the story: If you are concerned about reliability don't use a Smith and Wesson upper chambered in 5.45x39.

  9. #69
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    Broken firing pin

    Well guys, it's been a long time since this has been updated. But ST mailed me the FP. And I have finally began testing in the lab. 1st things first, there is absolutely no indication of this being a welded two pc firing pin, none.

    I have some more tests to perform on it before I'll be able to throw a rough pictorial report together so that all may understand.

    I will say this much, there are some unusual inclusions within the base steel. I doubt they had anything to do with the failure at all, it's just interesting with this grade of steel to see such gross inclusions.

    Tomorrow I'm going to check the grain size to see if I can reveal any instances of grain growth, or any other abnormality.

    But before I finish this post for now, the failure is a brittle fracture. What this means in layman terms is that it just snapped with no indication of ductile failure as a weld would exhibit before the surfaces give way in, on, or near a suspect hear affected zone.

    So we can at lease positively conclude, this pin is absolutely positively NOT welded at all.

    I'll report back more when I finish investigating it.

  10. #70
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    Jimmy Hoffa...... FOUND!

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