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AR-15 assembly hickup?

bambambambambambam Member Posts: 4,818 ✭✭✭
edited March 2013 in Ask the Experts
I just about have my gun all put together. Waiting on my handguards and the delta ring stuff to arrive. Still need to order a flash hider or comp.
DSCN0200.jpg

I was cycling about 6 rounds out of the mag into chamber then ejecting them to be sure the feeding and ejecting was working ok. I noticed when I put the ammo back in the box they had small primer strikes in them. I was pulling the charge handle back and letting it slam forward. Is the picture below normal?

DSCN0203.jpg
It' the six case on the right. Ammo is cheep WPA steel case.
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Comments

  • 11b6r11b6r Member Posts: 16,584 ✭✭✭
    edited November -1
    Yup. Free floating firing pin.
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  • Riomouse911Riomouse911 Member Posts: 3,492 ✭✭✭
    edited November -1
    Yup. Ol' Sir Isaac Newton's First law strikes again...

    http://teachertech.rice.edu/Participants/louviere/Newton/law1.html
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  • TxsTxs Member Posts: 17,809 ✭✭✭
    edited November -1
    That's completely normal for an AR or M16.

    EDIT:

    quote:Originally posted by yoshmyster
    Man that's kind a scary. If you got build up of crap on the firing pin that basically makes the firing pin stuck.Keep in mind that the bolt and bolt carrier are seperate components.

    The bolt carrier group is designed so that each time it cycles the carrier pulls the firing pin to the rear and away from the breech face.

    If the firing pin were unable to move to the rear the bolt carrier group would be unable to cycle.
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  • yoshmysteryoshmyster Member Posts: 21,974 ✭✭✭✭
    edited November -1
    Man that's kind a scary. If you got build up of crap on the firing pin that basically makes the firing pin stuck. Sounds like it's a good idea to make some dummies for feed and eject.
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  • Laredo LeftyLaredo Lefty Member Posts: 13,451 ✭✭✭
    edited November -1
    As mentioned, the dimpling of primers is normal in AR's even when using steel case ammo like pictured. Unlike many combloc guns, US guns have free floating firing pins, so when the bolt slams forward the firing pin is free to slide in the bolt thus making a mark on the primers.

    I once had a slam fire with an M1A when chambering a round without a magazine in place. If your testing your gun I strongly suggest you do it with a magazine in place to slightly slow the bolt carrier's speed or use dummy rounds.
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  • nmyersnmyers Member Posts: 16,891 ✭✭✭✭
    edited November -1
    And, NEVER EVER EVER install the bolt & bolt carrier in the upper receiver without the firing pin.

    Neal
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  • bambambambambambam Member Posts: 4,818 ✭✭✭
    edited November -1
    quote:Originally posted by nmyers
    And, NEVER EVER EVER install the bolt & bolt carrier in the upper receiver without the firing pin.

    Neal


    Ok, i'm curious, what happens if you do?
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  • sandwarriorsandwarrior Member Posts: 5,453 ✭✭✭
    edited November -1
    quote:Originally posted by bambambam
    quote:Originally posted by nmyers
    And, NEVER EVER EVER install the bolt & bolt carrier in the upper receiver without the firing pin.

    Neal


    Ok, i'm curious, what happens if you do?


    The cam pin can come out and possibly jam the rifle and cause damage.
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  • Rebel_JamesRebel_James Member Posts: 4,746
    edited November -1
    quote:Originally posted by sandwarrior
    quote:Originally posted by bambambam
    quote:Originally posted by nmyers
    And, NEVER EVER EVER install the bolt & bolt carrier in the upper receiver without the firing pin.

    Neal


    Ok, i'm curious, what happens if you do?


    The cam pin can come out and possibly jam the rifle and cause damage.


    Huh? If you leave out the firing pin the rifle won't fire ... Since it won't fire, how can it jam?? DUH!?
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  • TxsTxs Member Posts: 17,809 ✭✭✭
    edited November -1
    quote:Originally posted by Rebel_James
    Huh? If you leave out the firing pin the rifle won't fire ... Since it won't fire, how can it jam?? DUH!?
    Simply put, with this design the firing pin acts to maintain the alignment/orientation of a certain part within the bolt carrier group.

    Inserting the BCG without it can cause the entire thing to jam in the upper receiver.
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