Ar-15 dented primers but not firing.

Discussion in 'AR-15 Discussion' started by bullittsam159, Apr 4, 2012.

  1. bullittsam159

    bullittsam159 New Member

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    This only happens when bump firing. The primers are dented but do not detonate and it happens about 4 times per mag. Anybody had the same problem? Are there any upgrades I can do to fix it so it will bump fire more reliably?
     
  2. purehavoc

    purehavoc New Member

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    heavier hammer spring possibly , try different ammo and see if it does the same thing . timing may be off a bit, bolt not closed all the way when the hammer hits causing it to ride the carrier and causing a light strike . Head space issue but I doubt that one . .
    Got a pic of the light struck primer ?

    Second option
    Dont bump fire it :D
     

  3. ryguy00

    ryguy00 New Member

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    Are you absolutely sure its not the ammo? Usually when a primer is dented, the round will fire. Unless youre talking about a light primer strike which ive never encountered in my ar. I would try a different brand of ammo first before buying any parts.

    I know its not the same as your problem but i cannot run tula ammo in mine. It does not have enough power to cycle the bolt and leave the empty inside the chamber. All ammunition is not created equal.
     
  4. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    Post a pic of the "dent". It sounds like it may be the typical small mark made by the non-spring loaded firing pin. If you are bump firing you may be releasing the hammer before the bolt is locked. The AR is made to not fire out of battery so the hammer is not even hitting the firing pin.
     
  5. bullittsam159

    bullittsam159 New Member

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    Don't have any pics of the dented primers I'll take a pic when I shoot this weekend of I can get out. It happened with Remington .223 and federal 5.56 so I really hope its not the ammo lol. The primers have serious dents in them not small marks. They look about the same as the fired rounds, I was think maybe the hammer is following the bolt back until it's closed and hitting the primer but without enough speed to detonate but enough power to dent? Does this sound possible? Also probably not headspace as it only happens bump firing and the gun has more than a few thousand rounds through it.
     
  6. bullittsam159

    bullittsam159 New Member

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    Robo cop that sounds like it could be right. The primer dent looks to be as deep as the successful rounds though so idk. I know I'm not the only one bump firing so there must be a way to fix this.
     
  7. primer1

    primer1 Well-Known Member Supporter

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    I find a dented primer anytime I cycle a round (dpms) then eject it without firing. Being the nervous type, I showed it to the dealer and they said the same about the floating firing pin. Still makes me a little nervous.
     
  8. homelessguy01

    homelessguy01 New Member

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    I've heard of a guy using large pistol primers by accident when reloading and ended up dumping a mag. I think alot of semi centrefires can slighty dent the primer when the bolt slams home. So this guy having loaded pistol instead of rifle primers got quite a fright!
     
  9. FCross7

    FCross7 New Member

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    Here's an easy way to fix it:

    Stop bump firing. :D

    -Fred
     
  10. locutus

    locutus Well-Known Member Supporter

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    First, why on earth would you "bump fire???"
    If the weapon fires normally in normal firing, you don't have a problem.;)
     
  11. PlaysWithZombies

    PlaysWithZombies New Member

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    Never could understand why the hel some people insist on bump firing a perfectly good rifle :rollseyes:
     
  12. BenLuby

    BenLuby New Member

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    Can't understand it either. Your aim is thrown off while doing it. I'd rather make the rounds count than simply have nothing other than a lot of noise and cordite odor.
     
  13. locutus

    locutus Well-Known Member Supporter

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    I guess my viewpoint is simply if you feel an uncontrollable urge for full auto fire, enlist in the army. They've got millions of weapons already set up for full auto. and they pay for the ammo.:p
     
  14. bullittsam159

    bullittsam159 New Member

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    Why are you opposed to it and what do you mean make the shot count? Is my life dependent upon making that coke can explode? If you aren't going to help I don't need your condescending opinions. Why fire it at all? Because its fun. This is why I don't come on the forums often.
     
  15. bullittsam159

    bullittsam159 New Member

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    Thanks for the help to all the people who offered suggestions that were constructive. I just can't stand everyone being on the offensive ever time anyone posts something on here.
     
  16. BenLuby

    BenLuby New Member

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    No one went on the offensive. We just started discussing bump firing.
     
  17. bullittsam159

    bullittsam159 New Member

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    Sorry I didn't realize y'all were trying to help when you criticized the way I fire my guns and then told me to stop my problem when bump firing by not bump firing.
     
  18. JonM

    JonM Moderator

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    semi-autos arent designed to fire that fast. what your experiencing is called hammer follow. this means the trigger is releasing the sear before the bolt carrier has fully locked the bolt into the chamber.

    installing a heavier hammer spring will detonate a round outside the chamber leading to a catastrophic kaboom. the possibility is loss of life by you or a bystander or severe injury.

    even with a normal hammer spring this can happen. its good reason why things like the slidefire or bumpfire techniques are an astoundingly bad idea

    my prediction is that at some point someone is going to die doing this or using the slidefire from kabooming a gun that is not designed to run that fast.
     
  19. ColdIron44

    ColdIron44 New Member

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    I recently swapped out my first gas block, and after test firing and re-zeroing the rifle, I proceeded to bump-fire two 30 round magazines. I wanted to make sure I had the gas system perfectly in line, and that my tinkering did not throw the rifle 'out of time.' What better way to test this than sending 60 downrange in 30 seconds?! Now I said that to say this: I believe these other gentlemen have hit the nail on the head, but could the underlying cause be a timing issue? I'm new to the platform, and I'm just brainstorming here, but would y'all experts suggest that the poster experiment with different buffers, springs, extractors, etc. Maybe check gas tube cleanliness and alignment? Properly staked gas key? Well lubricated BCG? Unimpeded locking lugs? Seems like something must be causing the hammer to ride the bolt home...
     
  20. bullittsam159

    bullittsam159 New Member

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    Thanks Jon and cold iron. I definitely thing the hammer follow is the