5.56 barreled 223 Colt question...

Discussion in 'AR-15 Discussion' started by therewolf, Apr 17, 2013.

  1. therewolf

    therewolf New Member

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    I have a friend, yeah, that's the ticket, who

    recently acquired a Colt Match Grade HBAR AR15

    in 223 caliber(marked on the lower). The bull barrel is clearly stamped

    "5.56 NATO-1/7-HBAR".

    (Looks exactly like a Vietnam-era M-16)

    What I, er, HE was wondering is,

    is it safe to fire 5.56 ammo through this rifle, without risking

    damage to the bolt, chamber, upper, and springs, and latches

    and pins and washers and woodruff keys and stuff?

    I must apologize for my friend, because he knows less about

    ARs than Owe-bozo knows about ethics in government. TIA:)
     
    Last edited: Apr 17, 2013
  2. fsted2a

    fsted2a Active Member

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    The tricky part is the barrel. If it is chambered for 5.56, you are good to go on either ammo. If it is chambered for .223, then only use .223 ammo. The 5.56 ammo is slightly larger in diameter, and will occasionally stick, (on Colts less than others) so you will need remedial action. The rest of the parts can be used with either caliber (actually, if you wanted to switch to AK ammo, all you would have to do is swich the barrel and bolt- mechanically speaking of course, check the laws in your area before pursuing that action). What is stamped on the lower is for legal purposes.
     

  3. therewolf

    therewolf New Member

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    Thank you, sir.

    My friend feels the only thing worse than

    "Click, click, DOH! " is "Click, KA-BOOM!".
     
  4. locutus

    locutus Well-Known Member Supporter

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    The chamber is cut into the barrel. If the barrel is stamped 5.56 you're good to go.
     
  5. therewolf

    therewolf New Member

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    Thanks, I'll have a range report as soon as I get some

    business affairs in order here, go north

    and settle some family business, go further north and

    visit some relatives and friends, attend a wedding,

    and find some ammo for the range.

    Holding your breath might not be advisable,(unless you're

    standing behind me) but hey, I'm a lousy shot, anyway.;)
     
  6. clr8ter

    clr8ter New Member

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    Assuming it's a factory upper, wouldn't you defer to that marking? I assume the whole gun is not factory? As an interesting note, the 6920 I just bought is marked 5.56. No where else on any of the paperwork, or box is 5.56 mentioned. Only 9mm, 223, and 7.62......
     
  7. MisterMcCool

    MisterMcCool Well-Known Member Supporter

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    That's a lot of guns! :)
     
  8. clr8ter

    clr8ter New Member

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    OK, Colt LE 6920.:D
     
  9. Sniper03

    Sniper03 Supporting Member Supporter

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    The Receiver has nothing to do with the caliber. It is the barrel! So it is good to GO to shoot 5.56 or 223 Remington cal. ammunition having the 5.56 chamber. For example you can put a 6.8 SPC upper receiver and barrel group on the standard AR-15 Lower along with a 6.8 Magazine. Or 458 SOCOM and other calibers by just getting a complete upper!

    03
     
  10. therewolf

    therewolf New Member

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    DNK they marked uppers. The barrel, however,
    is marked ""5.56 NATO". The lower is marked
    "Colt".
    My issue was with whether the .223 upper
    could handle the brawnier 5.56 NATO
    caliber, with the heavier bullet weights.

    But now I, er, I mean my friend has to wonder if Colt marks it's
    uppers?
     
  11. clr8ter

    clr8ter New Member

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    OK, so I consider the upper to include the barrel, if thats how it was bought. I was under the impression that with 223 VS 5.56, bullet weight had nothing to do with anything. More like a higher pressure thing.
     
  12. therewolf

    therewolf New Member

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    If you check your reloading manuals, you will notice

    powder charges between .223 and 5.56 are minimally different,

    but the bullet

    weights of 5.56 are considerably heavier. Gives me the impression

    pressure at the chamber and bolt would be higher.
     
  13. fsted2a

    fsted2a Active Member

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    Wolf,
    It is entirely possible unless the entire gun was new in the box that the barrel was a replacement.
     
  14. highpowerguy

    highpowerguy New Member

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    The last time I checked there were 9 different chamberings of .223. With so many different chamber dimensions some of the manufacturers mark their lowers with 223 to limit their liability in the event that some one puts over pressured ammo in them. The lower receiver and upper receiver are not subjected to chamber pressure. The bolt locks into the barrel extension and all the pressure is contained by it. For this reason you should follow the markings on the barrel since the barrel extension is fitted to it before it is put on an upper. In my experience ar bolts are very strong and I can't ever recall hearing of one that wasn't designed to handle NATO spec pressures. You don't really hear of bolt problems until someone starts taking metal off of them deliberately (6.5 Grendel), or they get very old. Typically you will experience cases sticking in the rifle or primers being punctured if your ammo is creating too much pressure. Given the number of chamberings you should check your cases every time you try a new brand. Look at the back of the fired case, if the primer looks cratered or you can feel a ridge on it when you run your finger nail across it then stop and don't shoot that ammo in that rifle any longer. The statement that NATO ammo is wider is false . NATO cases have the same external dimensions as commercial cases. The side walls are often thicker but that affects the internal dimensions. The ogive however is a different story. The bullets in 5.56 ammo are usually longer than their civilian counterparts which causes them to be closer to the lands as the cartridge sits in the chamber this results in less bullet jump and higher chamber pressures. NATO spec chambers are cut with generous throats to account for this and reduce throat erosion. The chambers are cut wider, but that is to increase reliability in combat conditions not to accommodate a wider cartridge.
     
  15. therewolf

    therewolf New Member

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    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    I reload, so I will definitely be reboxing, saving, and repeatedly

    inspecting all fired casings. If you re-box at the range it saves you

    headaches later. And, uh, my friend saves money if I reload, too.

    Yeah...

    Thank you all for your assistance. Now we know enough to operate

    the firearm safely.
     
  16. therewolf

    therewolf New Member

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    So after a few hours of careful research, using the

    scant markings on the upper, turns out the bolt,

    carrier, upper, and barrel are all Colt.

    The rifling and chamber are pristine. We're

    looking forward to some range time with this

    unit.
     
  17. sniper762

    sniper762 New Member

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    if it (Looks exactly like a Vietnam-era M-16).........it aint a match grade
     
  18. fsted2a

    fsted2a Active Member

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    Without the background engineering knowledge to agree or disagree with you, the OP's question centered around could he fire ammo labeled 5.56 if the reciever was marked .223, but the barrel was marked 5.56. I still stand by my assertion that it is the barrel he should be concerned with, not the receiver. If he had Lake City 5.56 Ammo, and the Colt barrel was marked .223, I would be concerned, as he probably did have a vietnam era rifle. I've had issues in the past with M16's that were Vietnam era jamming on 5.56 rounds at the qualification range. We ended up changing out the barrels to solve the problem.
     
  19. highpowerguy

    highpowerguy New Member

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    I agree with that assertion the only reason I made the comments about the case diameter being the same is because saying otherwise would lead one to believe that 5.56 ammo shouldn't chamber in a .223 which would be quite false, they chamber just fine which is why there is a problem. I felt it was noteworthy to make the correlation between sticking cases and chamber over pressure. I was not trying to offend, having that information makes a person less likely to injure themselves or damage their equipment.