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Wednesday, November 16, 2022

.223 Rem vs. 5.56 NATO: What's the Difference?

You don't have to play in the AR playground very long before you hear or ask the question; "Does .223 vs. 5.56 matter?" The argument can reach near-religious proportions, with some on both sides vehemently arguing their cases. The deal is this: They do differ, and, yes, it does matter.

The differences really come into play with the starting path of the bullet and the unrifled portion of the chamber ahead of the rifling, called the leade. A narrower (less diameter) leade keeps the bullet from tipping as it moves forward, which enhances accuracy. A larger leade allows for more buildup and gunk and thus greater reliability.
-Alemaster

16 comments:

  1. All I know is I can shoot a .223 in my 5.56 but I cannot shoot a 5.56 in my .223. Both are .25 MOA accuracy with custom handloads.

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  2. I don't have these issues....7.62 x 51 baby!

    Chutes Magoo

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    Replies
    1. Isn't there some kind of difference between 7.62x51 and .308 Winchester?

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    2. Yup, the kliks on my gas port!

      Chutes Magoo

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    3. Yep. 7.62 chambers are looser, and the rounds are loaded to significantly lower pressure. You can wreck a NATO spec 7.62x51 rifle with hot .308 ammo loaded with heavier bullets.

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  3. http://www.ar15barrels.com/data/223-556.pdf

    Download the pdf. Compares dimensions of 8 different chambers.

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  4. Here are a couple of good in depth articles that shovel the bullshit away.

    https://www.luckygunner.com/labs/5-56-vs-223/

    https://ultimatereloader.com/2018/08/05/223-vs-5-56-facts-and-myths/

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    Replies
    1. Yep, virtually interchangable...the differences are in the chambers not the rounds.

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  5. Go Wylde - never go back

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  6. I have had this argument with many folks. Try as I may, I cannot stuff more than 25 5.56 rounds into a Mini-14 30 round mag before the mag jams up. The Cheaper than Dirt folks tried to ream me a new ass hole because "there is no difference" in the specs. I call bullshit.

    I just mic'd a dozen or so of each from several different manufactures. The 5.56 rounds mic out at 57.32 mm each; the .223 rounds mic out at 56.86 mm (for those math challenged folks, tha works out to just about 0.5 mm difference sustained). I saw variations of plus/minus 0.02 mm across the rounds in both calibers; mostly plus minus 0.01 mm. The empty cases were 44.85 and 44.81 plus/minus 0/05; but that is to be expected because they have been fired and I expect that there might be some differential expansion due to the chamber pressures.

    This jibes with my experience that I can put a 5.56 and .223 next to each other and tell immediately because of the different lengths of the rounds. Of course, I don't have the equipment to measure the dimension to the start of the ogive (?) where the round would start to make contact with the throat. But, anyone who says that there are no differences are either blind or something else.

    I know this will start a religious war, but I am seriously not interested in any person's rants.

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  7. I have a Bushmaster AR and a Mini-14. Both are safe queens as I prefer 6.8SPC in the AR platform and my 30-06 for deer hunting.

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  8. they use the same headspace gauge. that's close enough for government work. i've fired them interchangeably for over 40 years w/ no problem. i worked in the armament shop for uncle sam for 20 of my 30 years repairing everything that shoots, mos 45k50. the barrels are built to withstand any pressure variation you can find in factory ammo times two, at least. most blown up rifles can be attributed to barrel obstruction, faulty ammo, or excessive headspace due to wear. i liken this argument to "omg, its covid, quick put on a mask!!!"

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  9. My 2 cents worth.....I make sure all my AR's I buy have a barrel marked NATO... https://ammo.com/comparison/223-vs-556

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