5.56 Question.

Discussion in 'Large-Bore/Small-Bore Rifle/Shotgun' started by leo66, Sep 2, 2012.

  1. leo66

    leo66 New Member

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    Can you shoot .223 ammo in an AR marked for 5.56.I have heard both yes and no.Confused. Shooting a S&W M&P 15.
  2. Carne Frio

    Carne Frio Member

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    Yes, .223 is safe to shoot in a 5.56 marked firearm.
    I have been doing it for over 30 years.
  3. gdmoody

    gdmoody Moderator Supporting Member

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    Yes, you can.

    You should not shoot 5.56 in a barrel marked .223 because of higher pressure in the 5.56.
  4. leo66

    leo66 New Member

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    Thank you Carne Frio
  5. JLA

    JLA Well-Known Member

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    easy one to write down. The 5.56 chamber will shoot both safely. The .223 chamber will NOT shoot 5.56 safely. This applies to ANY .223/5.56 chambered firearm regardless of the action type..
  6. GunHugger

    GunHugger Well-Known Member

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    Don't go by what the receiver says, look for the caliber stamped on the barrel to know for sure.
  7. JLA

    JLA Well-Known Member

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    Excellent point GH. some AR lowers are stamped '5.56' or 'multi', whereas they could be fit with a .223 target barrel.
  8. polishshooter

    polishshooter Active Member

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    The 5.56 was developed first, and has very slightly different specs and pressures than the .223 Remington which was brought out commercially based on the 5.56, later.

    Kinda the same thing as the differences between 7.62x51 NATO and the later .308 Winchester, although not as big a difference. AND backwards...a .308 chamber WILL handle a 7.62 NATO round, but a .308 should NOT be fired in a NATO chamber, like an old Spanish 1916 ".308 Mauser" or an Ishapore MK 2....

    The 5.56 chamber specs are a VERY little bit bigger than the .223 to chamber any military ammo by any manufacturer, and it became even more important when it was adopted by NATO, now there was even more differences between countries of origin, and all rifles had to chamber anything available in 5.56 NATO.

    The .223 chambers are "tighter," if you look at SAAMI specs, and some very slightly oversize military rounds MAY develop excess pressure in a .223 chamber.

    While I know guys who claim they shoot milsurp from all over the world in their .223 bolt guns with no problems, I wouldn't chance it unless a SHTF emergency hit....

    But Rock River and Les Baer and others are offering ARs chambered in ".223 Wylde..."

    This is an old wildcat based on the same .222 magnum case that the .223/5.56 was based on, a little tighter than a 5.56 but not as tight as a straight .223 chamber so it still should shoot both safely, but with a slightly better potential for accuracy than a straight 5.56 chamber.
    Last edited: Sep 6, 2012
  9. leo66

    leo66 New Member

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    Thanks for all the help guys. This is why I love this place
  10. KWM

    KWM Member

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    I'm kinda lost here. 5.56 mm = .218897 inches. .223 inches = 5.6642 mm. The 223 is the larger round correct?
  11. GunHugger

    GunHugger Well-Known Member

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    [​IMG]
    Last edited: Oct 5, 2012
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