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Dent on primer

Discussion in 'Maintenance & Gunsmithing' started by FA9, Sep 30, 2014.

  1. FA9

    FA9 Hillsburrito, ORgun Well-Known Member

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    This is for an ar15. I put a round in the chamber by releasing the bolt, and extracted the cartridge right after. I noticed a tiny dent on the primer. Is that normal??

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    Last edited: Sep 30, 2014
  2. Joe13

    Joe13 NW of Vancouver Opinionated & Blunt Bronze Supporter 2015 Volunteer 2016 Volunteer

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    I'm gonna go out on a limb and say no...
     
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  3. Capn Jack

    Capn Jack Wet-Stern Washington Bronze Supporter Bronze Supporter

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    It's perfectly normal for an AR 15 to make a small dent, as the fireing pin floats.
    The design does require you to keep the your bolt clean and clean primer pockets during reloading to prevent "Slam Fires" due to high primers. :D

    Some reloaders stear clear of Federal primers when reloading for the AR as they are known to have softer than most cup material.
     
  4. U201491

    U201491 Well-Known Member

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    Strange. I have had Colts, Bushmasters, and Ruger SR's and none ever put a dent in any primer prior to actual firing. That would be extremely unnerving.
    I have looked and it seems to be very common. I looked at the SR and there is a mark like a rub mark, but it is not a dent per se.
    With the thousands of rounds I have shot, I have never seen what I would call a dent, but there sure seem to be a lot that do.
     
    Last edited: Sep 30, 2014
  5. Ben Beckerich

    Ben Beckerich NW Oregon Bronze Supporter Bronze Supporter

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    Totally normal

    Never chamber the same round twice, unless it's to fire. This isn't to prevent NDs (though it's a small possibility) but to prevent the primer from being damaged to the point that it WONT fire when you need it to. Cycle chambered rounds to the bottoms of other magazines
     
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  6. FA9

    FA9 Hillsburrito, ORgun Well-Known Member

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    ...
     
  7. rutilate

    rutilate Vancouver and Surrounds Active Member

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    .
     
    Last edited: Oct 1, 2014
  8. Doc In UPlace

    Doc In UPlace Tacoma-ish Well-Known Member

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    It is normal in my Colt 6920, regardless of the ammo.
     
  9. trevoro

    trevoro Coastal range Member

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    Yep. It's totally normal. ARs don't have a firing pin spring to hold it back when the bolt closes. The dent is just the firing pin inertia striking the primer lightly as the bolt comes to a stop.
     
  10. mike28w

    mike28w Idaho ! Member

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    I noticed it when I bought my Ruger SR556 and then researched it on the internet. It sounds like it's not uncommon. I couldn't find a report of the firing pin actually hitting hard enough to fire the cartridge in an AR. But I have seen the results first hand of slam fire in an SKS ( I work in a hospital)....not pretty.

    Nevertheless..... I installed a titanium firing pin ( it's lighter) and now it doesn't dent the primer and I feel better. Still want to point that baby in a safe direction ( just like all guns !! ).

    PS: If I ever found a mod that allowed for a firing pin spring on an AR, I'd be all over it !! (Hint to clever machinists !)
     
  11. chuck2669

    chuck2669 Seattle Area New Member

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    Make sure that your ammo is using #41 primers and not small caliber rifle primers. The #41 primers have a heavier (Thicker) cup to prevent slam fires. #34 for 7.62 rounds...
     
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  12. Ben Beckerich

    Ben Beckerich NW Oregon Bronze Supporter Bronze Supporter

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    bubblegumz over a year old, bru.
     
  13. Medic!

    Medic! What just happened? Has eagle eyes. But cant remember what he saw. Bronze Supporter

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    They have made a lot of Ar's and M-16's with the standard firing pin.
    They are safe. And more importantly they work.

    The mass of a titanium firing pin is less than a steel one. So you wont hit the primer now with as much force.

    The hammer spring dose most of the work. So you should be OK.
    But if you get ammo with a little harder primer the gun may not fire.

    If you totally remove the firing pin the gun will be extra safe!
    It just won't shoot.

    My point is. Don't fix it till it's broke! ;)

    Remember. The engineers that built the gun. Well.......... They were engineers.

    A lot of people buy cool parts.
    Just keep in mind. All parts makers need to do is sell parts.

    Gun makers need to make all the parts work together?
     
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  14. mike28w

    mike28w Idaho ! Member

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    Mr. Medic, I agree that one should be rather circumspect re: re-engineering.....That being said , I'm not sure that the M16/Ar platform is a particularly good posterchild for excellent engineering. Certainly there were some Vietnam vets that weren't impressed.

    The M4/AR platform has certainly evolved since then....

    If I were using an AR for self defense, I would stick with the steel firing pin....so in the end, we do agree.:) mike
     
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  15. Certaindeaf

    Certaindeaf SE Portland Well-Known Member

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    Yeabut what? Good luck trying to get a large rifle primer into a small rifle primer pocket.
     
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  16. oli700

    oli700 Rogue Valley Well-Known Member

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    that would be a change in the gun powder from a clean burning stick powder that the AR15 was designed around to a spherical powder with heavy calcium carbonate, the new powder also was a faster burn causing premature unlocking of the system leading to breakages, usually the bolt lugs.....after the rifle was proven, the rifle is a genius deign that went 80,000 flawless rounds in the proving
    The Army treated the symptoms instead of the illness and added a forward assist getting solders into worse trouble......finally the powder was fixed
     
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  17. mike28w

    mike28w Idaho ! Member

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    "That was then , this is now" I can't argue with that...........................mike
     
  18. ra glass

    ra glass pullman Member

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    If you are reloading, USE THE WHITE BOX CCI PRIMERS ONLY. These are made for the military. DO Not use any other primers for AR style weapons. This will still happen with the CCI primers. It's just the way it is, the firing pin floats. One of the best,and easiest weapons to work on.
     
  19. oli700

    oli700 Rogue Valley Well-Known Member

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    never have I loaded #41 for AR......thousands . In fact no one I shoot with uses them , never a problem
     
  20. Certaindeaf

    Certaindeaf SE Portland Well-Known Member

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    I wonder what all primers Nato/military/factory loads use? Guaranteed it's not "THE WHITE BOX CCI PRIMERS ONLY". feh