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Re-Loading 5.56 Questions

Discussion in 'Handloading and Reloading' started by KAC1911, Jan 29, 2010.

  1. KAC1911

    KAC1911 Well-Known Member

    I have a brand new set of 223 dies (Lee 2 die set).

    Can these be uses for 5.56?

    Do 5.56 & 223 cases have different (not mfg) head stamps?

    Both my reloading books just show 223 but also indicate 5.56, are most reloading books like this or do I need new manuals for 5.56 data?

    What I have read is that 5.56 has higher pressures than 223 hench the reason you shouldn't uses 5.56 in a 223 barrel so are case lengths different?

    Sorry for all the questions but trying to get a better handle on this.
  2. 243winxb

    243winxb Well-Known Member

    Dies work in both. Military has a crimped in primer. This crimp must be remover to reload. Case length/trim length same. Start low on the powder charge, work up. Read all here http://www.6mmbr.com/223Rem.html
  3. Walkalong

    Walkalong Moderator

    Dies are the same. Chambers can be different. Yes, you can fire .223 in 5.56 chambers, but supposedly not the other way around.
  4. KAC1911

    KAC1911 Well-Known Member

    Thanks 243, get site and article. Will take some time to devour all that but it help alot.
  5. 243winxb

    243winxb Well-Known Member

    Factory loaded Nato Military 5.56mm ammo, NOT to be fired in a tighter 223 rem chamber. http://www.saami.org/Unsafe_Combinations.cfm If you read the link above there are 3 or 4 different chambers for the round. The 4th being a tight match grade.
    Last edited: Jan 29, 2010
  6. Walkalong

    Walkalong Moderator

    There are exceptions, such as the Mini 14.
  7. rcmodel

    rcmodel Member in memoriam

    It's interesting to note that for about the first 30+ years after the introduction of the 5.56mm and .223 Rem in 1964, SAAMI made no distinction between the two.

    Ruger always marked the Mini-14 as a .223, and said in the owners manual you could shoot commercial or GI ammo in them.

    It's only been recently that SAAMI got their panties in a wad over the perceived difference when a bunch of lawyers had lunch together..

    I am only aware of two specific problems stemming from using 5.56mm NATO ammo in a .223 Rem firearm.

    Both were in 1970 something.
    One when some folks got some blown primers firing 5.56 in certain early SAKO Vixen .223 rifles that came into the U.S. with .223" bores instead of the proper .224" bores.

    The other was with some Remington 40X benchrest guns with minimum spec .223 Rem benchrest chambers.

    If we look at the history of all the gazillions of .223 Rem chambered rifles built in the last 46 years?
    And all the millions of rounds of stolen and surplus 5.56MM ammo fired in them?
    And all the thousands of .223 gun owners who never heard of the SAAMI warning before the internet, or bothered to read the warnings in the owners manuals more recently?

    You could count on the fingers of one hand the number of problems there have been reported. None involving blown-up rifles or personal injurys.

    The only two problems I know for a fact are true and really happened 35 years ago are the SAKO Vixen & Rem 40X blown primer issues I mentioned above.
    And they didn't hurt the rifles or the shooters.

  8. Randy1911

    Randy1911 Well-Known Member

    Quoted by Walkalong

    There are exceptions, such as the Mini 14.

    Quoted by rcmodel

    Ruger always marked the Mini-14 as a .223, and said in the owners manual you could shoot commercial or GI ammo in them.

    I own a Ruger Mini-14 and have read this.

    I have wanted to try loading some 5.56mm, but I can't even find load data labeled as 5.56mm NATO. All I can find is 223 Rem. Is it available anywhere?
  9. Walkalong

    Walkalong Moderator

    I've never seen any "5.56" data either, just .223. Trust me though, if you want to try some surplus 5.56, the Mini will just gobble it up and spit it out. No worries.
  10. alsaqr

    alsaqr Well-Known Member


    SAAMI did not publish their alarmist stuff until 5.56mm surplus military ammo became widely available. Been firing and reloading .223/5.56mm ammo for over 40 years. During that time I've fired a few hundred thousand rounds of 5.56mm military ammo in about 15 different .223 chambered guns without a problem.

    BTW: SAAMI is the same outfit that asked the ATF for new regulations for the manufacture, storage and transportation of commercial ammunition and reloading supplies. After the ATF published the draft pub for review SAAMI had a conniption.
  11. steve4102

    steve4102 Well-Known Member

    Nosler #6 has data labled 223 Remington and data labeled 5.56 Nato. It's basically just 223 data with bullet weights from 69gr and up. Their 223 data stops at 60gr.

    If you want to load 5.56 Nato loads just load your 223 hot. The 223 is spec-ed out at 55,000psi and the 5.56 is spec-ed out at 62,000+psi. That's about it.
  12. KAC1911

    KAC1911 Well-Known Member

    Thanks again guys for the help. Been wanting to get/build a ar-15 and have been a reloader for a while but never did 223. So I started looking for 5.56 specific stuff and everything is 223. I noticed in my manuals both of them only have bullet data up to 55 grain 224 bullets and there has been a lot of advancement in the range of bullet weight and design.

    I bought a lee 2 die set in late 70's early 80's and never used them. Even bought a tool that lets you adjust bullet position in the shell to set up different oal for a better jump from bullet to rifle lands. I think it was from a company called Sinclair or something. I ended up buying a 22-250 instead so I never used these dies.
  13. rcmodel

    rcmodel Member in memoriam

    Nosler & Hornady both have 5.56mm specific load data chapters.

    But as already noted, the only difference is, they list 5.56mm data for heavy bullets as used in 1/7 & 1/9 twist barrels.

    It makes no sense to list those heavy bullet loads in the .223 chapter, because up until very recently, all commercial .223 rifles used slower twist rifling that would not work with heavy bullets.

    This is true.
    But, SAAMI and NATO measure pressure differently, and in a different location in the barrel.
    It's comparing apples & oranges if you try to compare the two measurement systems and the results they come up with directly.

    Most of your modern load data in reloading manuals is listed in CUP anyway, which makes it even more irrelivent.

    For instance, Lyman #49 lists a .223 Rem, 63 grain load at 3,250 FPS at 50,400 CUP.

    And that's 5.56 NATO performance any way you measure it, even if it is listed under .223 Rem load data..

  14. steve4102

    steve4102 Well-Known Member

    Of all my manuals, Lyman 48 is the only one to list pressures at all. Load data from the powder manufacturers is a little better. Hodgdon and Accurate still list in both CUP and PSI while Ramshot lists in all PSI. Wouldn't it be nice if some day this would all be standardized, so we didn't have to compare "apples to oranges"?

    Quickload lists the following,
    223 Rem
    62,366 PSI
    Piezo CIP

    223 Rem SAAMI
    55,000 psi
    Piezo SAAMI

    5.56 Nato
    62,366 psi

    How's that? Confused yet? I sure am. Anyone care to shed some light on the three different measuring methods listed here?
  15. alsaqr

    alsaqr Well-Known Member

    Got to page 10-3 of US Army TM 43-0001-27. The pressure of the US Army military M193 ball round is 52,000 psi as measured with a piezo-electric transducer.


    CUP is Copper Units of Pressure using the antiquated copper crusher system. It does not directly measure anything. A copper pellet is placed in a hole in the receiver of a test gun. The hole is directly over the cartridge case. The gun is fired and the copper pellet is miked to find out how much it was crushed. A table is consulted to find the CUP. The CUP rating gives us only the highest pressure obtained. CUP does not readily convert to PSI.

    The piezo-electric transducer system can give a time-pressure curve as well as the highest pressure obtained. For your reading enjoyment:


    SAAMI is the US system.

    CIP is the European system. Much European ammo is loaded hotter than SAAMI spec.

    NAAG stands for NATO Army Armaments Group. NAAG uses a very sophisticated and state of the art system to measure the pressure of a few different NATO small arms rounds.

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