Identifying 5.56 brass vs. .223 brass

Discussion in 'The Powder Keg' started by Airweight38, Jul 10, 2010.

  1. Airweight38

    Airweight38 G&G Newbie

    Joined:
    Jul 13, 2008
    Messages:
    333
    Location:
    Kansas City
    I'm getting started reloading .223 ammo for my AR and I have a LOT of range brass to go through and sort.

    .223 ammo is unique in that a lot of the headstamps are cryptic and don't come out and say .223 or 5.56 caliber. Which begs the following questions:

    1) Is there a measurement I can take with my calipers that will clue me in as to which is which? Or is there a "headstamp database" somewhere where I can cross-reference the headstamps to see what's what?

    2) Is there enough of a difference for this to even matter? What will happen if I reload a 5.56 case using my .223 dies?

    Thanks. I've been reloading for awhile, but this is only the second rifle caliber I've done...
  2. SwedeSteve

    SwedeSteve Freedom Zealot Forum Contributor

    Joined:
    Feb 17, 2007
    Messages:
    33,734
    Location:
    Anchortown, Alaska
  3. sniper762

    sniper762 G&G Enthusiast

    Joined:
    Jun 15, 2004
    Messages:
    1,101
    Location:
    NorthCarolina
    the differences are neglable
  4. gandog56

    gandog56 G&G Enthusiast

    Joined:
    Oct 8, 2006
    Messages:
    26,693
    Location:
    Mobile, Alabama
    Generally, .223 says .223. If it's just numbers or letters, it's probably 5.56. I load them both, but do separate them.
  5. Ten Man

    Ten Man G&G Newbie

    Joined:
    Jul 28, 2009
    Messages:
    10,002
    Location:
    Pacific Northwest
    I agree with gangog56

    There are only two reasons you should be concerned about the difference: Brass wall thickness, and OAL of the case.

    The reason brass wall thickness is a concern is because the thicker wall reduces overall volume, thus increasing pressure under ignition.

    The OAL is a concern only because the throat of the barrel on a .223 and a 5.56 have a different leade space. As long as they are all trimmed to spec for the lesser dimension, there is no problem.

    I have found that the Military 5.56 brass is usually cryptic, and DOES NOT have .223 stamped on the head. IF the brass is stamped .223, I load it for the higher pressure loadings for bolt action rifles. If it is stamped any other markings than .223, I reserve them for AR 15 pressure loadings.

    Of course, this demands good record keeping, and the separation of the different ammos.

    The simplest way to go about it is to simply load ALL of your brass to mil-spec. loads, assuming the thick wall cases, and then you have no problem. The drawback to this is the inability to maximize the loads for your accurate bolt action rifles. As always, it's a trade-off.:swordfight:
  6. wunhunglo

    wunhunglo G&G Newbie

    Joined:
    Dec 23, 2007
    Messages:
    5,268
    Location:
    currently "Sunny West Africa"
    As mentioned the basic rule of thumb is: If it's stamped .223REM it is .223 if it's not stamped it's almost certainly 5.56 and if it's not stamped and the primer is crimped it's almost 100% definitely 5.56mm. Almost forgot, if it's just numbered/lettered but has the NATO symbol it is 100% 5.56 nato.

    There are plenty of Headstamp data books available but you never know how up-to-date they are. "Times they are a changing," to quote Dylan (I think) Google can also be your friend here!

    The external dimensions are the same, no problems using the .223 dies (as a matter of fact, I have never seen any 5.56mm dies anywhere- now I'll be proved wrong LOL)

    The issues are; when reloading you should sort your cases by headstamp and if changing headstamps you should work the loads back up again and never assume that the same load in different headstamped cases will be OK.

    Always check your fired cases for excess pressure signs.

    I personally use Lapua cases in my 1 in 7" bull barrel & RG cases in my 1 in 8" Hbar barrel. KISS principle. (it works for me)
    Last edited: Jul 11, 2010
  7. Airweight38

    Airweight38 G&G Newbie

    Joined:
    Jul 13, 2008
    Messages:
    333
    Location:
    Kansas City
    Thanks for the replies, guys! I wasn't aware of the whole NATO thing. That's helpful.

    I always sort by brand and always trim my cases, so I should be alright. Seems I heard somewhere the shoulder height was different on 5.56 or whatever, but maybe that's an urban legend. That or the full-length sizer corrects it?

    Also, I have the min and max load both at 26.2gn of Winchester 748 for my 55gn FMJ, so there's not much building up to do, fortunately. They seem to shoot fine, though the primers seem flatter than factory loads, so I'm a little curious about that? I get the same thing on my .357 loads and was told on another thread that that's okay as long as there are no other signs of pressure.

    Thanks again for all the help!
  8. gandog56

    gandog56 G&G Enthusiast

    Joined:
    Oct 8, 2006
    Messages:
    26,693
    Location:
    Mobile, Alabama
    If there was a difference in the shoulder, and I'm thinking there isn't, full length sizer die should fix it, yep.
Similar Threads
Forum Title Date
The Powder Keg Need Help Identifying This Track: Jun 25, 2012
The Powder Keg Need help identifying antique gun Jun 17, 2010
The Powder Keg Identifying a 1911? Jan 29, 2010
The Powder Keg Need help identifying a Shotgun Nov 29, 2009
The Powder Keg Help Identifying Rifle Nov 29, 2009