difference between 223 and 5.56

Discussion in 'General Rifle Discussion' started by michael80, Dec 11, 2012.

  1. michael80

    michael80 New Member

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    What is the difference between 223 and 5.56 in all the conversations I have had with the people I work with I have got 15 different answers and none make any sense to me can some one please inform me properly.
     
  2. silverado113

    silverado113 New Member

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    It has been covered but, The primary difference between .223 Remington and 5.56 is that .223 is loaded to lower pressures and velocities compared to 5.56. .223 Remington ammunition can be safely fired in a 5.56 mm chambered gun, but the reverse can be an unsafe combination. The additional pressure created by 5.56 mm ammo will frequently cause over-pressure problems such as difficult extraction, flowing brass, or popped primers, but in extreme cases, could damage or destroy the rifle. Chambers cut to .223 Remington specifications have a shorter (throat) area as well as slightly shorter headspace dimensions compared to 5.56 mm "military" chamber specs, which contributes to the pressure issues.
     

  3. jcd390

    jcd390 New Member

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    I was wondering the samething, thanks Silverado for the explanation.
     
  4. JTJ

    JTJ Well-Known Member Supporter

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    Siverado got it right. The problem is mostly in the chamber. Most guns would shrug off a 10% over pressure but that 10% can climb to catastrophic in the wrong chamber configuration.
     
  5. silverado113

    silverado113 New Member

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    You're welcome.
     
  6. Sniper03

    Sniper03 Supporting Member Supporter

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    Michael,

    They are not the same. The Throat on the 5.56 Chamber has a longer lead. While a "True 223 Remington Chambers lead is shorter. The Head Space on both are the same but the Chamber Lead is different in length. One should never shoot a 5.56 NATO round in a "True" 223 Remington Chamber" This is very obvious if you were to check the Chambers of both with a Throat Erosion Gauge. If you will go here in the Forum and find a Thread by me dated 8-23-11 Entitled Throat Erosion Gauge you will see pictures of the Throat Erosion Gauge and it's use. With the Throat Erosion Gauge inserted into the Receiver and looking straight down at a 90 degree angle as shown the "True" 223 Remington would only insert roughly before the First Line on the Throat Erosion Gauge from the tip of the gauge that is in the chamber and throat of the barrel. If it is a 5.56 NATO Chamber it will insert in until the the second or second and one half line prior to the third line. Some manufacturers have a slightly more open lead in their 5.56 chambers. Please see the Thread listed above! There is also one other issue. 5.56 Ammunition has higher pressure than commercial ammunition. Bottom line do not shoot 5.56 NATO Ammunition in a Remington 223 Chamber. All prominent name brand AR Rifles are 5.56 NAT0 or a Wylde Match Chamber which will shoot 5.56 equally as well.

    03
     
  7. jjfuller1

    jjfuller1 New Member

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    what they said^^

    its kinda like a cars seatbelt, you wear it because something could happen. does it always happen no.. but it could. thats why we always advise to not shoot 5.56 out of a .223 chamber... but a 5.56 chamber can shoot both safely
     
  8. michael80

    michael80 New Member

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    Thank you very much for passing on your knowledge.
     
  9. 303tom

    303tom Well-Known Member

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    None..............
     
  10. jjfuller1

    jjfuller1 New Member

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    false.. even if you dont like the idea of non interchangability.

    check all the measurments.. even though very little, there is a difference.
     
  11. Overkill0084

    Overkill0084 Active Member

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    Mods, since this comes up fairly regularly, perhaps this or one of the other resultant threads could be awarded "sticky" status?

    http://en.wikipedia.org/wiki/5.56x45

     
  12. InDefenseofLiberty

    InDefenseofLiberty New Member

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    Here is the best explanation from a guy who has shot and tested a crap ton of AR style weapons and REALLY knows his stuff. Well worth the read if you really want to be informed.
    http://www.luckygunner.com/labs/5-56-vs-223/
     
    Last edited: Dec 11, 2012
  13. silverado113

    silverado113 New Member

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    Great article and should be a sticky
     
  14. Sniper03

    Sniper03 Supporting Member Supporter

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    If you ever have any question get a Throat Erosion Gauge and measure the two of them. I have won a lot of free drinks over this in past years. Some of the newer military rifles have even a slightly longer lead over the standard 5.56 due to the fact the chamber is designed to shoot tracer rounds.
    Most in the commercial market will never have exposure to this.
    03
     
    Last edited: Dec 11, 2012
  15. 7point62

    7point62 Lifetime Supporting Member Lifetime Supporter

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    And while we're on the subject of comparison the same cannot be said for .308 vrs 7.62 Nato which are identical pressures, although the NATO spec brass is a tiny bit thicker.
     
  16. hoovco

    hoovco New Member

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    Uh, no go. There's about 15,000 psi difference there. .308 shouldn't be used in a rifle chambered for 7.62 NATO.
     
  17. hoovco

    hoovco New Member

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    Correction: 12,000
     
  18. 303tom

    303tom Well-Known Member

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    I use .308 Win. in my 2A exclusively & have for years, they just shoot better.............
     
  19. jeremyx28

    jeremyx28 New Member

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    I'm not trying to discredit anything already said but, 5.56 can be shot from a saiga rifle chambered in 223. There is a stickie on the saiga 12 forum directly from the manufacturer. I personally have shot about 200 rounds of 5.56 out of my saiga 223 without an issue. I'm not saying that its true for all or any other rifle other than the saiga.
     
  20. Threetango

    Threetango Audentes Fortuna Iuvat Supporter

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    Fortunately my Bushmaster MOE 308 is set up to fire both.

    I did find the Luckygunner link 5.56 vs .223 – "What You Know May Be Wrong"
    good info.