5.56x45 or .223rem?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by meatyrem, Jan 28, 2011.

  1. meatyrem

    meatyrem Well-Known Member

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    I have a question about rifles in the .223 rem and the 5.56x45 NATO. Can they both be shot out of the same rifle? For example; Ar 15 chambered in the NATO round, can that fire the .223 rem also? Or vice versa? There is a question that a rifle chambered in one cannot shoot the other. If I remember correctly, a rifle chambered in 5.56 NATO can shoot both, but a rifle chambered in the .223 rem cannot shoot the NATO round. Just looking for clarification on this issue. Thanks for any help.

    Meatyrem
     
  2. Trickymissfit

    Trickymissfit Well-Known Member

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    the rounds are the same (case), but the throats are slightly different. You'll see a very slight pressure spike (I mean very slight).
    gary
     

  3. meatyrem

    meatyrem Well-Known Member

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    I was always on the assumption that either one can be fired through a rifle chambered in a 5.56 NATO. And either one can be fired through a rifle chambered in .223 rem. There is a fella that said one will fire both but not the other way around. So if there is a slight difference, then will it harm the rifle in any way? Or should it be avoided just to be safe?
     
  4. Trickymissfit

    Trickymissfit Well-Known Member

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    without chamber and throat drawings right in front of me, I can't exactly tell you the difference. But I do know it's in the length and angle of the throat. If I remember right the 5.56 is a few thousandths longer in the throat, but with a wider throat angle (I'm sure somebody will correct me). Sorta like a very short free bore. But the cartridge case and length are the same
    gary