This should answer your question you had about .223 and 5.56

Discussion in 'Ammunition & Reloading' started by fredball, Nov 8, 2015.

  1. fredball

    Vancouver, WA
    Well-Known Member

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    This should answer your question you had about .2223 and 5.56 rounds and AR vs AK: Which is Better?

    Is There a Difference Between .223 and 5.56
    The comparison between .223 and 5.56 isn’t a new one, so there is a lot of discussion to weed through to learn about the two. Ultimately, because they originated from the same cartridge, they are very similar, but that does not mean that they are necessarily interchangeable. This article discusses three key differences between .223 Remington and 5.56x45mm NATO.
    .223 Remington and 5.56x45mm Dimension Measurements

    At a glance, the two rounds are indiscernible. Both rounds use a bullet of .224in in diameter and an overall length of 2.26in. In general, the external dimensions for the two calibers are identical. What’s more significant is the pressure of the two rounds and the difference in the rifle chambering.

    .223 Remington and 5.56×45 Pressure Measurements

    One of the problems with comparing these two cartridges is that they utilize different methods of measuring pressure. SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) measures the .223 pressure at the center of the casing, whereas the NATO standard measures the pressure at the throat (or leade) of the chamber. To rectify the two different methods, several have undertaken experiments with their own standardized recording method to compare “apples to apples.” One such thorough study was carried out and recorded in detail by Andrew Tuohy posted via Lucky Gunner Labs (click here to read the full article). Tuohy evaluated various .223 and 5.56 ammo fired through rifles chambered for .223 Remington and 5.56x45mm.

    His, and the research of others, confirms that, generally, shooting .223 through a 5.56 chamber results in lower pressure, but still functions (safely). Firing 5.56 through a .223 chamber, however, results in somewhat higher pressures. Although the differences aren’t massive (~5% in the previously referenced study), extensive firing of 5.56 through a .223 chamber could lead to over-pressure malfunctions, such as popped primers or blown cartridge case heads and other firearm malfunctions.

    .223 Remington and 5.56×45 Chamber Differences

    The most important difference between .223 and 5.56 chambers is the length of the throat (or leade) for each chamber. More specifically, the leade is located at the mouth of the barrel before the rifling occurs. Comparing the NATO and SAAMI regulations, the leade for 5.56 chambers is nearly twice as long as that of a .223 chamber (.162in to .085in, respectively). If a 5.56 round contacts the barrel rifling too early, it can cause pressure spikes (leading to malfunction, and potentially damage) in the chamber. This explains why it is safe to fire .223 through a 5.56 chamber, but not recommended to fire 5.56 through a .223 chamber.

    Which should you choose?

    As with so many elements of making a firearm purchase, the “right” option is subjective. If all you intend to purchase are .223 Remington rounds,

    There is nothing wrong with getting a rifle chambered for .223. However, if you want the option of firing milspec 5.56 through your rifle, you may prefer

    Picking up a 5.56 chambered rifle. After all, you can still fire the .223 through it, safely, if you want. Price and personal preference are also factors to

    Consider when making that decision. What works for you?


    AR vs AK: Which is Better?

    Published on June 26th, 2014 | by Destinee (FateofDestinee)
    Submit to reddit 1

    One of the fiercest, and longest running, debates within the firearms community is this: which is the better “battle rifle:” the AR or the AK. The topic has been done to death, so I thought I’d feature the two rifles in a different setting: working together. The video embedded above features an AR-15 and an AK-74.

    The featured AR, like many rifles of its type, is a custom build. Some of the key components included are a DI Daniel Defense DDM4V7LW upper, a LMT Defender lower receiver, and Troy flip up battle sights. On the other end of the spectrum, the AK74 I’m wielding above is a standard milsurp rifle. This Romanian SAR-2 is in the same condition now as when I first cleaned off the cosmoline, except, well, dirtier.

    Some argue that the AK-74’s 5.45×39 cartridge is the Eastern European answer to the AR-15’s 5.56×45 NATO round. On the range, I’ve found the perceived recoil to be similar, but let’s look at some measurable data. The AR’s 5.56×45 has a standard muzzle velocity of about 3,100 FPS, compared to the AK-47’s 7.62×39’s average muzzle velocity of about 2,300 FPS. The AK-74’s 5.45×39 round flies between the two at about 2,900 FPS.

    What is my preference? Both. I think the AR-15 and AK-74 each have their merits and demerits. I enjoy the remarkable volume of options for customizing AR style rifles. Between uppers, lowers, barrels, triggers, grips, stocks, hand guards, muzzle devices and more, there are countless options for completely unique AR builds. Although, these kinds of rifle builds have a way of running off with your wallet. Military surplus firearms, like my AK-74, are often acquired for considerably less coin. The AK-74 in this video cost about one third the overall price of the AR-15 firing next to it. It also bears mentioning how reliably my AKs have performed on the range, as compared to my AR style rifles. Over the years, AKs have established a reputation of being nigh impossible to impede their ability to fire. Thousands of rounds of carbon fouling? Mud? Sand? Ham sandwich? No problem. The AK-74, like its big brother AK-47, will take all kinds of abuse and keep on kicking.

    When it comes down to it, the “better” rifle is really a matter of personal preference. Which is your favorite?
    Nick Burkhardt and DuneHopper like this.
  2. erudne

    The Pie Matrix
    PPL Say Sleeping W/Your Rifle Is A bad Thing?

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    thanks for the post, I have never had a problem shooting 556 through a 223 chamber. Mil-spec chambers are routinely looser than civvy chambers
  3. The Heretic

    The Heretic
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    Much the same has been said of 7.62x51 v .308 Winchester

    But I have never had any problems with either 5.56 nor 7.62 in any rifle (and I have shot a lot of military ammo in them) regardless of the rifle and that includes both the FR8 Mauser and the Ishapore Enfield (both have some people warning that these rifles are weaker or poor quality or have some safety problem).

    That doesn't mean that somebody somewhere hasn't had problems, that maybe they attributed, correctly or incorrectly to the differences between chamber and loading specs for military and civilian cartridges. I just think that if there were any serious issues that we would see much more widespread problems.

    Most modern firearms (i.e., post 1900) are built with modern steel and can take quite a bit more pressure than what their cartridges generate - even if there is a 5% pressure increase.

    But to each their own.
  4. The Heretic

    The Heretic
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    For the most part, most current era rifles can handle these kinds of failures without injury to the shooter.

    So I have a question: who here has personally had a problem of this sort (that could be attributed to the differences in loading pressure and/or chamber specs) with military 5.56x45 or 7.62x51 ammo (not reloads) in a civilian modern era rifle chambered for .223 Remington or .308 Winchester?

    The closest thing I have heard of is some higher pressure loadings for 7.62x51 military ammo meant for LMGs, and even there, it was a caution, not an incident.
  5. Stomper

    SHUT YOUR FACE!! Gold Supporter

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    I've always been under the impression .308 was slightly hotter than 7.62x51 NATO....
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  6. Steve M

    Steve M
    Beaverton, OR
    Well-Known Member

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    I've got an AR chambered in 5.56, an M1A in 7.62, and a 7x57 Mauser whose chamber was cut a couple decades before SAAMI came into being. None of these was manufactured to SAAMI specs yet I've still got all 7 fingers.
  7. mjbskwim

    Well-Known Member

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    And for more old news.... Ruger's mini 14,despite the barrel being stamped 223,will in fact shoot the 556 round without any problems
    Per Ruger's own web site
    No I won't show a link cause I'm eating dinner
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  8. Dyjital

    Albany, Ore
    Flavorite Member Bronze Supporter

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    Ruger had two stampings ".223 Cal" and ".223 Rem"

    The .223 Cal were fine for 5.56. They had the longer freebore.

    Guess what the ".223 Rem" was made for? (Earlier models of non Ranch Rifles had this, while the ranch rifles had .223 Cal).

    Any new ones today say ".223 Cal" (except the target model which is made for 223 only)



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