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.223 vs 5.56

Discussion in 'Shooting Related Threads' started by skeet_man, Jul 21, 2013.

  1. skeet_man

    skeet_man Well-Known Member

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    You can shoot .223 in a 5.56 gun, but you CANNOT go the other way.
     
  2. redfin1956

    redfin1956 Active Member

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    from what i have read,yes. the throat is longer on the 556,for higher pressure and longer bullets.i am building an ar at work. i went with a 556 chamber to shoot mil ammo.check out accurateshooter.com bench rest site,and read the section on 223. joseph
     
  3. Big Al 29

    Big Al 29 TS Member

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    the leade (throat of the chamber) in the 556 is twice as long as the 223.

    So... 556 can not shoot in 223 chamber

    But... 223 can shoot in a 556 chamber

    You can "force" a 556 into a 223 but you dont want the bullet laying on the rifling because of the pressure. 556 are already higher pressure loads and combining them with a smaller chamber like the 223 chamber you could be asking for trouble.
     
  4. GW22

    GW22 Active Member

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    Click link.

    -Gary

    PS: It's not as simple and absolute as you might think. I once saw a buddy trying to shoot .223 in his newly acquired AR-15 which had no caliber stamped into the bbl. The bolt absolutely would not close. Turns out it was a 5.56. Hmmm.
     
  5. pfofml

    pfofml Member

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    I shoot 5.56 military rounds thur my 223 Rem 700. Dose this mean that this may damage the barrel?
    Peter
     
  6. Shooting Coach

    Shooting Coach Well-Known Member

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    Lots of good info on this. The throat is longer on the 5.56mm. Headspace is the same, but 5.56mm headspace gauges are more "generous", due to the lack of camming power of the autoloading feature.

    The chamber on an autoloader MUST be generous enough to allow positive chambering when gun is heavily fouled. I prefer .004" headspace on bottlenecked cartridges, autoloader or not.

    My Browning HB Varmint has a Wilde (hybrid) chamber (and.004" headspace), and is marked .223/5.56mm.
     
  7. CalvinMD

    CalvinMD Well-Known Member

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    That's the great thing about Bushmaster use of the Wylde chamber..a hybrid that can and does shoot both with match accuracy
     
  8. mag410

    mag410 Active Member

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    Peter,

    If your 700 .223 Rem has a long throat, you are "probably" ok.

    If it has a short throat and .223 leade, then you are asking for trouble.

    Are you seeing any pressure signs in the fired brass?

    Michael
     
  9. pfofml

    pfofml Member

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    Mag410
    The fire fired cases show no signs of excesive presure. Also the military ammo I am using is head stamp indicates is manufacture date as 1968. Groups nicely.
    Peter
     
  10. Brian in Oregon

    Brian in Oregon Well-Known Member

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    brianinoregon_2008_030328.jpg


    The cartridge dimensions are the same. It would be an unusual .223 that would not chamber a 5.56.

    The differences are the throat lead for the chambers and the higher pressure loads of the 5.56 cartridge.

    The 5.56 has a long throat lead. This allows loading to a higher pressure, because the bullet can freely travel a short distance before engaging the rifling. Weatherby did the same with their chambers.

    The .223 has a shorter lead. Because the .223 was intended to be a sporting cartridge, accuracy was the important consideration. That's why it has a shorter lead. The bullet engages the rifling sooner and that helps with accuracy. The trade off is this increases pressure.

    The .223 has a nominal working pressure of 55,000 psi while the 5.56 spec is 62,000 psi. This is a 13% difference. However, it should be noted that some .223 loads are up in the 5.56 region and they do not have issues.

    Will chambering a 5.56 in a .223 chamber harm the gun?

    The answer is a gray area. I have yet to find a genuine, documented, first hand case of a gun blowing up. I know one person who claims he had a blown primer. In the last 30 years my friends and myself have shot plenty of 5.56 in guns marked .223 without any problems.

    One area that can be harmed is the throat. Because of the hotter loading, a steady diet of 5.56 can cause throat erosion sooner in a .223 chamber. HOWEVER, the same thing can be accomplished with hot .223 loads, and even powder type is a big consideration. Ball powder is a bit more forgiving for erosion, as it has less of a sandblast effect than extruded powder. (This is one reason I prefer ball powder in my guns that shoot high volumes of ammo.)

    For actual shooting, I have noticed a difference in recoil when shooting 5.56 in a .223 marked gun. SOME of them have a bit more recoil, which you would expect from higher pressures. Others have no difference at all.

    BTW, some manufacturers are confused as to what they actually chambered the gun as. Remington states their version of the AR15, the R15, is chamber for .223 Rem "only", and it is marked .223. Bushmaster made the gun, and an engineer from Bushmaster is on record as saying that's nonsense, the gun can chamber 5.56 because the throat is longer. It's supposed to be a .223 Wylde chamber. Apparently Remington did not want to put 5.56 on the barrel, but also did not want to confuse people with a .223 Wylde stamping.

    Some manufacturers have even stamped their barrels as .223/5.56. My Browning 1885 Single Shots are so marked. However, I've never fired a 5.56 in them.

    What should you do?

    Well, if you want to play it on the safe side, then shoot exactly the ammo your gun specifies on the barrel.

    Or have a gunsmith make a chamber cast to find out exactly what the chamber is. It's known that some manufacturer's have stamped .223 on the barrel but the chamber is a 5.56 or a .223 Wylde.

    And if you have a .223 and want to maintain accuracy, don't shoot 5.56 in it, as this can erode the throat sooner. (See notes above, because a hot .223 will cause the same erosion).

    You can also modify a .223 to a 5.56, or better yet, modify it to a .223 Wylde chamber. A competent gunsmith can simply ream the chamber. (Note that this should not be done on chrome lined bores, but, I've never seen a .223 chrome lined bore, only 5.56, so this is probably a moot point.)

    If you have a .223 upper and want to use it with .223 only for hunting, then get a 5.56 upper as well and blast away with cheaper 5.56 ammo. There are plenty of used 5.56 uppers at gun shows if you want to save money.

    What did I do?

    I have several 5.56 rifles and they get fed mainly 5.56 but sometimes .223 for hunting. I also have some old .223 rifles that have had piles of 5.56 through them in the last 30 years, long before the 223/5.56 difference came to light.

    These days my hunting .223 rifles only get .223, not because of the pressure issue, but because I want to protect the throat so as to maintain accuracy as long as possible in them.
     
  11. SKB-Eric

    SKB-Eric Member

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    I have a Savage 10 Tactical in .223 and I called them directly to ask about 5.56 --- they told me it was perfectly fine to shoot any military 5.56, as this rifle was designed for military / LE use. This came right from Savage.

    So, I guess a blanket statement of no 5.56 in a .223 is not 100% correct to say. Check with the rifles maker when in doubt.

    Eric
     
  12. Bill T

    Bill T Active Member

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    I don't even segregate my 5.56 MM brass from my .223 anymore because there is no difference. People make far more of this then need be. Can anyone show me a gun that was actually damaged by shooting 5.56 MM in a .223 Chamber? You can't because there aren't any. The Internet keeps this myth going, along with plenty of general firearms ignorance.

    The only difference is freebore of the chamber, and that will not cause enough of a rise in pressure to be concerned about. It's no different with Weatherby ammunition. It is designed to be shot in Weatherby rifles that have more freebore in their chambers. You can safely shoot it in any other make weapon chambered for any of the Weatherby Magnum calibers that DO NOT have the same amount of freebore, such as the Remington 700. All to do about nothing. Argue about Muslims. It will be more rewarding and entertaining.