Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

5.56 verse 223 question

Discussion in 'Rifle Country' started by taozen79, Jul 15, 2009.

Thread Status:
Not open for further replies.
  1. taozen79

    taozen79 Member

    Joined:
    Jun 1, 2007
    Messages:
    14
    I have a ar15 A1 , I believe, colt upper , barrel marked
    C MP C

    can it shoot 5.56??????

    THANKS for any help

    Buddy
     
  2. taozen79

    taozen79 Member

    Joined:
    Jun 1, 2007
    Messages:
    14
    HELP 'bumped"

    HELP
     
  3. cyclopsshooter

    cyclopsshooter Member

    Joined:
    May 13, 2009
    Messages:
    2,241
    Location:
    The Shadow Knows...
    dont know for sure but my best guess is 223 but even a 223 can shoot some 556 but its nt always reliable
     
  4. taozen79

    taozen79 Member

    Joined:
    Jun 1, 2007
    Messages:
    14
    markings

    BARREL:
    DIAMETER:
    0.625" at the Front Sight Base
    LENGTH:
    20"
    TWIST RATE:
    1/12
    MARKINGS:
    C CM C
     
  5. NGIB

    NGIB Member

    Joined:
    Dec 11, 2007
    Messages:
    885
    Location:
    Hinesville, GA
    As it was explained to me by folks I trust:

    If chambered for 5.56 - can shoot either 5.56 or .223

    If chambered for .223 - can only safely shoot .223 (headspace & pressure differences)

    What's stamped on the gun, 5.56 or .223?
     
  6. freakshow10mm

    freakshow10mm member

    Joined:
    Apr 20, 2008
    Messages:
    1,951
    Headspace is the same, leade is longer in the 5.56.

    Pretty sure Colt chambers all their guns 5.56.
     
  7. nhm16

    nhm16 Member

    Joined:
    May 23, 2009
    Messages:
    94
    Yes, even the early ones marked ".223" on the lower receiver.
     
  8. taozen79

    taozen79 Member

    Joined:
    Jun 1, 2007
    Messages:
    14
    BARREL:
    DIAMETER:
    0.625" at the Front Sight Base
    LENGTH:
    20"
    TWIST RATE:
    1/12
    MARKINGS:
    C CM C

    this barrel is older than the ones marked 5.56. it is an sp1
    By 1969 and before serial number 1,750,XXX Colt's chrome chamber barrels were marked C MP C, and the proof markings and C were moved to the same spot. This marking was used as late as 1970 or 1971 and serial number 4,552,XXX. The C means Colt’s, the M means Magnetic particle inspected, the P for Proof fired, and the C near the muzzle for Chrome chamber. (late C MP C pic provided by yfs200):
     
  9. freakshow10mm

    freakshow10mm member

    Joined:
    Apr 20, 2008
    Messages:
    1,951
    The barrel marking is the key, not the lower.
     
  10. taozen79

    taozen79 Member

    Joined:
    Jun 1, 2007
    Messages:
    14
    BARREL:
    DIAMETER:
    0.625" at the Front Sight Base
    LENGTH:
    20"
    TWIST RATE:
    1/12
    MARKINGS:
    C CM C
    this is the barrel markings....from the colt sp1
     
  11. Byron

    Byron Member

    Joined:
    Jan 2, 2003
    Messages:
    1,029
    Location:
    TN
    I have a AR bought in 1978.It has had a lot of 5.56 put through it and never failed to function and stays accurate. Byron
     
  12. Lone_Gunman

    Lone_Gunman Member

    Joined:
    Dec 24, 2002
    Messages:
    8,056
    Location:
    United Socialist States of Obama
    Colt's AR's have 5.56 chambers... you are good to go.
     
  13. SaxonPig

    SaxonPig Member

    Joined:
    Apr 11, 2006
    Messages:
    4,787
    #32


    223 vs. 5.56 (and .308 vs. 7.62x51).

    32. There is essentially no difference between commercial .223 and military 5.56 ammo. The same is true with .308 and 7.62 ammo. The military stuff has slightly thicker brass with a tiny bit more length in the shoulder and I hear this is for strength when feeding through full-auto guns that tend to slam the rounds into the chamber violently. But otherwise, there doesn’t appear to be any difference that I have noted after many years of shooting both military and commercial ammo through my .223 and .308 rifles, both bolt action and semi-auto although with some guns with tight chambers closing the bolt on military ammo can be a bit snug. It is a popular misconception that military 5.56 ammo is loaded to higher pressures than commercial .223 but it is not.
     
  14. briansmithwins

    briansmithwins Member

    Joined:
    Aug 1, 2005
    Messages:
    4,132
    Good explanation. Too bad SAAMI doesn't agree with you. BSW

    From: http://www.saami.org/Unsafe_Combinations.cfm

    In Firearms Chambered For---Do Not Use These Cartridges
    223 Remington--------------5.56mm Military
     
  15. MT GUNNY

    MT GUNNY Member

    Joined:
    Aug 19, 2006
    Messages:
    1,450
    Location:
    Kalispell MT
    "Essentially" there is a Difference:
    View attachment 223vs556.pdf

    However upon Lots of Discussion And First hand Accounts. You can Safely Shoot .223 in a 5.56 Chamber. But the Opposite, Possible Damage to your Firearm.
     
  16. John Parker

    John Parker Member

    Joined:
    May 14, 2009
    Messages:
    679
    Just shoot it and let us know.
     
  17. nalioth

    nalioth Member

    Joined:
    Jul 9, 2007
    Messages:
    5,841
    Location:
    Houston, Texas
    If I might point out that it doesn't make sense to expect a fast response when you post during the work day.

    Also, "bumping" the thread after a half hour without a response isn't going to send out psychic waves to get everyone to immediately run to their keyboards to answer you.

    Please don't do this any more.
     
  18. Uncle Mike

    Uncle Mike Member

    Joined:
    Nov 5, 2008
    Messages:
    3,129
    Location:
    never never land...never land here!
    Here's an idea... call up Colt and put the question to them.
     
  19. taliv

    taliv Moderator

    Joined:
    Oct 23, 2004
    Messages:
    22,372
    it's popular because, iirc, the 5.56nato max avg pressure number is a good bit higher than the .223rem ....buuuuuut... units matter and one is in CUP and the other in PSI, so good luck comparing
     
  20. tju1973

    tju1973 Member

    Joined:
    Feb 25, 2008
    Messages:
    471
    Location:
    Texas
    Search is your friend--

    .223 is safe in 5.56 chambers, not always the other way around...

    Some mfgs are marked .223, but 5.56 is ok--ie Mini 14s...

    Always go by the MFG recommendation...
     
  21. ScrwnyM4

    ScrwnyM4 Member

    Joined:
    Jul 1, 2009
    Messages:
    20
    There is in fact a difference between 5.56 and .223. The pressures for 5.56 are higher. If you are chambered for 5.56 then you can shoot both, it is not recommended to fire 5.56 out of a gun chambered for .223. Click on this site if you want proof. It is from Winchester's own site. http://www.winchester.com/lawenforcement/news/newsview.aspx?storyid=11
     
  22. SHvar

    SHvar Member

    Joined:
    Oct 14, 2008
    Messages:
    648
    There is around 12,000 psi more to a 5.56 over .223. Call colt, ask them, Im sure they will tell you that the chamber is 5.56X45mm.
     
Thread Status:
Not open for further replies.

Share This Page