.223 vs. 5.56

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  • Rating - 0%
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    Dec 2, 2008
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    I have got some questions as to the difference between the two of these calibers. I know one difference is a few thousands of an inch in headspace, but I am wondering what is the difference is in ballistic performance. I understand that the 5.56Nato is the military round, and have been told that it is a higher pressure round, and that most surplus ammo is no good for reloading. I know that varmint hunters seem to prefer the .223 because it is more accurate (so I have been told) and it appears to be more small game hunting ammo available in that caliber. So besides these differences, is there any velocity difference, and any difference in general availablity of ammo (especially now). Do these calibers share any uses such as coyote hunting, or other small game. What I am really after in all this is--how do these rounds differ in performance? Thanks
     

    Panama

    Shooter
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    Jul 13, 2008
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    Googled and found this:

    News and Press Releases
    .223 Rem VS 5.56mm Paul Nowak5/4/2001.223 Rem VS 5.56mm

    There are a lot of questions about these two cartridges. Many people think they are identical - merely different designations for commercial and military. The truth is that, although somewhat similar, they are not the same and you should know the differences before buying either cartridge.


    • The cartridge casings for both calibers have basically the same length and exterior dimensions.
    • The 5.56 round, loaded to Military Specification, typically has higher velocity and chamber pressure than the .223 Rem.
    • The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader.
    • The 5.56mm and .223 Rem chambers are nearly identical. The difference is in the "Leade". Leade is defined as the portion of the barrel directly in front of the chamber where the rifling has been conically removed to allow room for the seated bullet. It is also more commonly known as the throat. Leade in a .223 Rem chamber is usually .085". In a 5.56mm chamber the leade is typically .162", or almost twice as much as in the 223 Rem chamber.
    • You can fire .223 Rem cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity over firing the .223 round in the chamber with the shorter leade it was designed for.
    • Problems may occur when firing the higher-pressure 5.56mm cartridge in a .223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads and gun functioning issues.
    • The 5.56mm military cartridge fired in a .223 Rem chamber is considered by SAAMI (Small Arm and Ammunition Manufacturers Institute) to be an unsafe ammunition combination.


    Before buying either of these two types of ammunition, always check your gun to find what caliber it is chambered for, then buy the appropriate ammunition. Most 5.56mm rounds made have full metal jacket bullets. Performance bullets - soft points, hollow points, Ballistic Silvertips, etc. - are loaded in .223 Rem cartridges. Firing a .223 Rem cartridge in a 5.56mm-chambered gun is safe and merely gives you slightly reduced velocity and accuracy. However we do not recommend, nor does SAAMI recommend, firing a 5.56mm cartridge in a gun chambered for the .223 Rem as the shorter leade can cause pressure-related problems.

    Winchester Law Enforcement Ammunition
    East Alton Illinois
     

    Old Syko

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    Nov 7, 2008
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    I guess all these 50 cal ammo cans I have setting around full of Lake City 5.56 and RORG brass that I've reloaded will just have to be thrown in the trash after reading this. Yep, hold your breath until that happens!:rolleyes:

    The pressure limit differences between Mil-spec and commercial ammo, 60,000# and 50,000# respectively, may be an issue to the inexperienced handloader who is not yet familiar with the proper use of load manuals. Load by the book and all is good.

    The amount of freebore or leade varies between Mil-spec and commercial chambers, but then again, it varies from one gun to the next also so leade becomes a nonissue. In ARs for example the magazine determines the COAL rather than the chamber doing so.

    Military brass being heavier than commercial is also an old wives tale. LC '02 to '08 is some of the lightest available. (Depending on lot) Competent handloaders always sort brass by capacity and/or headstamp before loading, especially to max loads. In my experience Federal commercial has been some of the softest and least welcome to me and my uses.
     

    Panama

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    Old Syko

    That was pretty much what I thought........but I am honestly not that knowledgeable or experienced on hand loading, so I thought I would search Google to see what I found, and even then, I wasn't sure what I found was 100% correct.

    I think I'll trust your experience, MORE than I'll trust Google's search results.

    Thanks for confirming my suspicions!
     

    Old Syko

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    Nov 7, 2008
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    Old Syko

    I think I'll trust your experience, MORE than I'll trust Google's search results.

    Thanks for confirming my suspicions!

    Don't trust me whatever you do. My wife made that mistake 37 years ago and look what it got her.:rockwoot:

    Bottom line is, as long as you match the right ammo to the right firearm there is little chance of a problem. Since very few people have access to pressure testing equipment we're all kind of flying by the seat of our pants when dealing with the 10,000# pressure difference allowed between 5.56 and .223. I've seen tight chambers and tight bores on conventional bolt action guns contribute to a higher pressure difference than this, but even knowing that just be careful. It's always better to err on the side of safety.
     

    EvilleFirepower

    Plinker
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    Dec 4, 2008
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    Most mil surplus ammo uses Berdan primers instead of Boxer which makes them tricky to reload if you are planning to do so.
     

    Old Syko

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    Most mil surplus ammo uses Berdan primers instead of Boxer which makes them tricky to reload if you are planning to do so.

    Actually it doesn't. Most is boxer primed just like commercial. There is still some surplus available being imported from foreign entities that are Berdan primed but they are usually in calibers originating from such foreign entities. I'm unaware of any 5.56/.223 presently available that is Berdan Primed. I'm also unaware of any Berdan primer availability at this time, and Berdan and Boxer are not interchangeable.
     

    jeremy

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    Feb 18, 2008
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    I will and have shot .223 through my 5.56mm, however I will not do the reverse. The military measures pressures in a different fashion. Which could possibly prove fatal for a .223 firearm.
    Just my 2 cents here.
     

    PFS

    Plinker
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    Dec 15, 2008
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    Great Information

    I recently bought 2 5.56 Smith and Wesson M&P Model 15's. I was not aware of the major difference in the ratings between the .223 and 5.56. If I am right, the 5.56 designation will take both types. If this is still active, I would like to know if I am right or wrong. Thanks again
     

    Cwood

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    May 30, 2008
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    I recently bought 2 5.56 Smith and Wesson M&P Model 15's. I was not aware of the major difference in the ratings between the .223 and 5.56. If I am right, the 5.56 designation will take both types. If this is still active, I would like to know if I am right or wrong. Thanks again


    You are correct, you can use .223 in a 5.56 chamber just don't do the reverse.
     
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