223 Remington vs 5.56x45mm reloading help

Discussion in 'The Ammo & Reloading Forum' started by mtls44555, Feb 26, 2012.

  1. mtls44555

    mtls44555 New Member

    Feb 26, 2012
    Hello, I am new to reloading my own rounds and I have this book that gives me all of the information on how to do so. It does not how ever tell me the measurements the 5.56x45mm, can i use the 223 Remington measurements ? Are they the exact same and is it safe to use that type of ammo in my (Stag)AR-15?
    Any help would be appreciated.
  2. BlackEagle

    BlackEagle Well-Known Member Supporting Member

    Nov 25, 2011
    Welcome to the forum, mtls. You're sure to find lots of help here. There are some real experts here who will be more than glad to help. Enjoy the rest of the forum, while you're here.

  3. Conman

    Conman Well-Known Member

    Dec 30, 2010
    Eastern Iowa
  4. JLA

    JLA Well-Known Member

    Feb 26, 2007
    Heart Of Texas
    Only difference is 5.56X45 rifles have a longer leade and are proofed for higher pressures.

    Yes you can use the .223 dies and measurements to load 5.56X45
  5. JLA

    JLA Well-Known Member

    Feb 26, 2007
    Heart Of Texas
    BTW, Im gonna move this thread to ammo and reloading.
  6. steve4102

    steve4102 Former Guest

    Jan 27, 2006
    First, welcome!

    Second, what do you mean by "measurements" ?

    The 223 Rem and the 5.56 are identical as far as the handloader is concerned, only the lead/throat in the rifle chambers differ. You use 223 dies and 223 loading data.
  7. mikld

    mikld Well-Known Member

    Jun 24, 2009
    This comes up often enough to become a sticky. How about it JLA?

    I first ran into this "problem" a bunch of years ago, when I was shooting 5.56 surplus in my .223 Handi Rifle. I got pierced primers with 5.56 ammo (mebbe 4-5 out of 20), but not so with factory .223, 50 grain SP. I believe it was 55 grain FMJ, which is on the edge for stability with a 1-12" barrel...
  8. American Leader

    American Leader Well-Known Member

    Mar 1, 2011
    Welcome aboard mtls44555 from the "GREAT STATE OF IOWA"!
  9. JLA

    JLA Well-Known Member

    Feb 26, 2007
    Heart Of Texas
    Ill stick it if it helps. :)
  10. OldFotoMan

    OldFotoMan New Member

    Feb 15, 2012
    Aside from what has been said already, and to help clarify it; There were 2 different 5.56 loads and a 223 load. The 2 5.56 cases are the same, but loading data is different for the M193 and the SS109 rounds due to the 1 in 12 twist for the original 193 and the 223 and the 1 in 7 twist of the SS109. The main difference in the cases is that the 5.56 brass is thicker, and so uses less powder to create the same pressures. So if you're loading 223 brass, you can certainly use 5.56 loading data and work up from there for hotter loads. But if you're loading 5.56 brass, using 223 data will create too hot of a load to begin with. Stick with the data for the 5.56 to begin loading that brass. Also, check the gun you're going to use them in to see what the rifling twist is, and start with the proper loads for that twist no matter which cases you are loading. In short, to be safe, always start with the lowest charge or weakest load, then work up for what is safe in your gun. What's safe in one may not be safe in another. Know your gun and match your loads to it. This takes trial and error, or advise from someone else loading for the same gun is always a great help. Cartridges of The World is a good reference (it gives you all of the measurements you'll need) to give you some factory and hand loading data that has been tested, and there are many other good reference books for hand loading available also.
    Last edited: Feb 29, 2012
    Crpdeth likes this.
  11. dammitman

    dammitman Active Member

    Feb 1, 2009
    so, does all this mean that all the high pressure was all due to the "leade" of the barrel and not to any of the load data unless one takes into account the "tiny" amount of space that is taken up by the thicker case of a 5.56 military case that isnt manufactured into a 223 case? and would all this high pressure concern be easily dismissed as long as any round would fit into a factory magazine whether military or civilian because that would eliminate the concern of "leade"? only "so long" a round will fit into a magazine and function, and its pretty short.
    Last edited: Mar 10, 2012
  12. BlackEagle

    BlackEagle Well-Known Member Supporting Member

    Nov 25, 2011
    The rule of thumb I learned and seems to work OK for me is to use 10% reduced charge for military brass. So, if the data book calls 25 grains of powder a maximum, (for a conventional case) use 22.5 as a maximum charge for military cases.

    I find that maximum loads for conventional cases can fill a military case too full.
  13. dammitman

    dammitman Active Member

    Feb 1, 2009
    that really sounds like good info and advise, i want to load some of that new CFE223 hodgdon powder and seem to have boatloads of military brass but alas no info directly for military brass but will just decrease the start by 10% as suggested. then cronograph and inspect fired brass as well as check overall accuracy of actual shots. i genuinely enjoy working up specific loads using same bullets, powder, primers and brass made to be specifically for one specific gun to be the perfect, most accurate developed round for that gun, then make buttloads of it!!!
  14. cpttango30

    cpttango30 Guest

    For the most part Mil brass for the 556/223 is not very different.

    Before you all start blasting away. Read the 6mmbr.com article about 223/ 5.56.

  15. BlackEagle

    BlackEagle Well-Known Member Supporting Member

    Nov 25, 2011
    Great link, Tango;
    I saw that site some time ago, and it is well worth the re-read.
    Thanks for the reminder. ;):thumbsup:
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