.223/5.56 brass

Discussion in 'Reloading' started by thumbs, Feb 25, 2014.

  1. thumbs

    thumbs Well-Known Member

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    Ok, I always thought the brass was different between .223 and 5.56. I am seeing more and more bolt rifles "listed" as .223/5.56. I "think" this incorrect but want to ask. The only one I know of is the Mossberg MVP. I know I can safely shoot .223 in a 5.56 chamber but not 5.56 in a .223 chamber. Now is the brass different or is the load different? I know the 5.56 creates higher chamber pressures that is not recommended for .223 chambers.

    Now the question is if I load 5.56 brass to .223 specs is it perfectly safe to shoot in a .223 chamber?

    In other words is there any physical difference in .223/5.56 bass. I was just looking at a once fired brass supplier and it lists the brass as .223/5.56 and say it's mixed. If the .223 chamber is different than the 5.56 this would seem to be a dangerous practice.
    So whats the truth about .223/5.56 brass.

    thanks for the help
     
  2. FEENIX

    FEENIX Well-Known Member

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

    [ame=http://www.youtube.com/watch?v=-iE7E7O4vTM].223 vs 5.56 Is there a difference? - YouTube[/ame]
     
  3. thumbs

    thumbs Well-Known Member

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    Thanks just watched the video. His focus is the AR. I shoot .223 and 5.56 reloads,not to max, interchangeably in the rifle. Of course it is chambered in 5.56 no worries. My question can I shoot 5.56 brass in a .223 chamber? Of course it would be loaded to .223 spec. My question is other than maybe the thickness for the case will 5.56 brass fit properly in a .223 chambered bolt rifle?

    In other words if i load my 5.56 brass to .223 specs will they fit in a .223 chambered bolt rifle safely?

    The reason I ask is I have a bunch of 5.56 brass and am in the process of looking for a .223 bolt rifle. I just want to know if I can load this brass to .223 spec and shoot them in the bolt rifle.
     
  4. Trickymissfit

    Trickymissfit Well-Known Member

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    .223/5.56 brass is identical except for the primer crimp. But with exception here! Military brass (ala Lake City) is often manufactured with thicker case walls, but still identical externally.

    There are differences other than the numbers:

    * 5.56 on paper looks identical as I said, but the SAMMI spec lists it at about 10% hotter. The .223 is maxed at 55,000psi, and the 5.56 is maxed at either 60,000 or 61,000psi. Black Hill loads most of what we call Lake City, and they load it to about 58,000psi. In a modern bolt action rifle, you'll never know the difference. Yet in an AR15 chambered in .223 you might well know the difference.

    * The 5.56 chamber is what the real difference is between the two of them (.223/5.56). With the 5.56, the throat is cut a little differently. The throat angle is cut a little narrower, and maybe a tad shorter. Add this in with the higher chamber pressure spec, and you get the warning label

    * now it's advisable to down load military brass to a starting load; if not slightly less yet. Simply because the case volume is a little less.

    Most of us on this board are shooting bolt action rifles that are well made. They'll easily hold up to 5.56 pressure specs when shot in a .223. We're looking at rifle built to a 75K psi spec! Then you factor in the case head diameter of .378, and that's nothing like the .470" or .532" ones.
    gary
     
    Last edited: Feb 25, 2014
  5. thumbs

    thumbs Well-Known Member

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    Ok thanks. This is for argument sake of course and not for practice but..... I think what your saying is the modern .223 rifles will hold the 5.56 pressures. It is possible to load the .223 round to 5.56 pressures and the modern rifles will hold the pressure. Now just to be sure. I am not able to check my load books. Other than the thickness for the cases the outside detentions for both the .223 and the 5.56 are the same. The only difference in the two rounds are they way they are loaded and the OCL right? So, theoretically, the brass will fit in both chambers the difference is in the way the cases are loaded correct? This being the case, if in fact it is, I can use .223 and 5.56 brass interchangeably as long as the loads are to .223 spec Right?

    Just want to make sure. Since I am looking at a bolt rifle I need to know if my brass will work. Not trying to whip a dead horse just trying to make sure I understand accurately.

    thanks
     
  6. pdog2062

    pdog2062 Well-Known Member

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    I have been using military brass for 30 or more years in my 223 rifles without a problem.The brass is generally the same capacity as the civilian brass contrary to popular belief.
     
  7. thumbs

    thumbs Well-Known Member

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    Do you just load it to .223 specs right??
     
  8. 556

    556 Well-Known Member

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    I have a bolt action in 223 and an AR 15 with a 5.56 chamber. I use military brass in my bolt action loaded to 223 load specs. My bolt action has a standard 223 chamber so I keep my loads to 223 specs. In my AR I have loaded to 5.56 specs. but not to often as I don't find it necessary for majority of my shooting. My AR accuracy is always better when loads are not pushed to the max.
     
  9. thumbs

    thumbs Well-Known Member

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    The reason I am asking is I am in the process of looking for a bolt .223 rifle. I have a .223 Wilson case gauge. If I drop a loaded 5.56 round in it it should fit the gauge like a .223 round right?? I am going back and forth between a Savage 16 and the Mossberg predator. I'll probably go with the savage if it will work with the .223 loaded 5.56 brass.
    Yeah I would rather only load one load for both.
     
  10. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    The throat is longer and the origin of the rifling is a bit shallower in 5.56 ammo to accommodate the higher pressures encountered. You will most likely get 5.56 ammo to fit in a 223 chamber, but you should load to milder specs and watch for interference in the throat. I see no reason for the external case dimensions themselves to be different; they are loaded with the same die sets.
     
  11. thumbs

    thumbs Well-Known Member

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    Well that makes sense. They are loaded with the same dies. Why didn't I think of that ?
     
  12. 556

    556 Well-Known Member

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    Lefty7mmstw is correct, you will have no problem using military 5.56b brass in your rifle with a .223 chamber. You can shoot 5.56 ammo in a rifle with a 223 chamber. I know a lot of people who do, however I believe it's dangerous and a practice I will not do because of the higher pressures. Best of luck.
     
  13. Trickymissfit

    Trickymissfit Well-Known Member

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    depends on the rifle your shooting. An AR chambered in 5.56 will shoot both well. Yet an AR chambered in .223 is different. Pressure spikes alone may end up in a disaster. Every ammo manufacturer issues this disclaimer. Also case volume with military brass is less than standard .223, so you get much higher chamber pressures with .223 loads. My loads using Lake City brass come in with a grain and a half less powder for the same velocity.
    gary
     
  14. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    I don't notice any pressure issues between the two head stamps but I'm usually either lc or fed. I also use rather slow burning powder in a 5.56 chamber so I'm a lot less likely to have an issue to start with.