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Author Topic: AR-223 ammo in a .223?  (Read 549 times)

Grant

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AR-223 ammo in a .223?
« on: November 26, 2013, 01:46:15 PM »
  Okay...federal makes two lines of "bulk pack"  AR556/XM193 those are stamped LC with the date and with the nato cross (whether it actually is or not I don't care) and a line called AR223 where the headstamp actually SAYS 223 and "Federal" on the headstamp.

 Okay...my question. Even the stuff stamped .223 seems to be loaded to 5.56 levels.  IE 55 FMJ to 3240 FPS, 50 grain JHP to 3320 FPS.

  SO....Even though it's labeled .223, is it actually 5.56?   IE can I shoot it out of my Winchester M70 .223?  I bought a good batch of the 50 JHP on deal ($10 a box).    I planned on shooting it out of my 20" AR15, but overall I use it so rarely for varmints I'd just as soon run it through my bolt gun.

Montana"I’d say the worst part of all this is the feeling of betrayal,           but I’m betting the part where they break in here and beat us to death might be worse.”


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Mississippi556

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Re: AR-223 ammo in a .223?
« Reply #1 on: November 26, 2013, 02:38:46 PM »
My take on it is that the LC brass has visible heat annealing and has crimped primers but otherwise they are probably identical, given the velocity specs.   The action on your bolt gun is going to be a good bit stronger than your AR, so I don't see a problem.  [EDIT:  See second post below.]

I'd do this first:   Run both loads through your AR and chrono them at 10 feet to see if they are clocking identically and consistent with the labeling.  I don't know what test barrel Federal used, so they are likely to run a bit lower than published, but I'd look for consistency between the two.  Borrow a chronograph if you don't have one.  Consider buying one.  They are cheap now.

At least shoot both on a target and see if they shoot to the same point of impact.  If so, and there is no discernible difference in recoil or how quickly the action cycles, then they are probably equivalent.   Common sense.

Next:  If all is well, then test fire one of the LC loads in your bolt gun and check for any pressure signs, such as flattened case head, shiny marks on the head, change in effort to lift the bolt, etc.  The rifle will handle it, but if you get extraction problems or pressure signs, you will not want to consider the ammo interchangeable and should relegate the LC to your AR only.

Chamber dimensions are slightly different, but the ammo is the same dimensionally.   The 5.56 ammo can exceed SAMMI pressure, but I'll bet that it does not because Federal knows it will be fired in non-5.56 chambers.

Caveat:  I don't have a .223 bolt gun, so I've not tried this personally.  Maybe someone here has direct experience in running 5.56 ammo in a civilian Model 70.
« Last Edit: November 26, 2013, 03:49:21 PM by Mississippi556 »
Mississippi"When a strong man, fully armed, guards his own palace, his goods are safe"  Words of Jesus, Luke 11:21 (ESV).

cpaspr

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Re: AR-223 ammo in a .223?
« Reply #2 on: November 26, 2013, 02:41:26 PM »
As I understand it, if the gun is a true 5.56 gun, you can shoot either.  If it is a .223, you should not shoot 5.56 in it.  The pressures are higher.

Similar but opposite, you can shoot either .308 or 7.62x51 in a .308 rifle, but don't run .308 win ammo through a 7.62x51 rifle.  It's hotter.
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Mississippi556

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Re: AR-223 ammo in a .223?
« Reply #3 on: November 26, 2013, 03:17:11 PM »
^  In principle, I agree.  But, I don't think Federal's current XM193 is as hot as M855, which we know is much hotter.   

The boxes marked .223 are clearly safe in both rifles.   I think the XM193 can be safely tested first in the AR and then in that modern Winchester bolt rifle for signs of pressure, especially if the rounds chrono the same and shoot to the same point of impact in the AR first.   Only if there is no discernible difference in this test would I even consider the test shot in the Model 70.

This is 55 grain ammo and the only significant difference in chamber specs is the leade - the distance between the case mouth and the rifling.   

To be safe, Grant might want to contact Winchester and see what they say regarding chamber specs.  I'm inclined to believe that if it is of recent production the chamber has been reamed to allow much longer bullets, anyway.

However, I do recognize that this is not without risk.  Here is an article on the subject from a writer that I respect, recommending against doing it.

http://www.americanrifleman.org/articles/223rem-vs-556-whats-in-a-name

« Last Edit: November 26, 2013, 03:50:39 PM by Mississippi556 »
Mississippi"When a strong man, fully armed, guards his own palace, his goods are safe"  Words of Jesus, Luke 11:21 (ESV).

Grant

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Re: AR-223 ammo in a .223?
« Reply #4 on: November 28, 2013, 04:54:12 PM »
  It's an older early 90's vintage M70.  I doubt it was made for longer bullets like that.

   I'm not especially worried about the pressure of it, I was wondering about throat erosion,etc.  :hmm  I've got 250 rounds of the 50 grain JHP's, and if it shot good I had been going to buy more.  I could just burn through them and then resight in for my old ammo (Ultramax 55 SP).

   That said it has probably....near 15 or 20 thousand rounds through it in it's life so that worry is already probably long gone  :cool
Montana"I’d say the worst part of all this is the feeling of betrayal,           but I’m betting the part where they break in here and beat us to death might be worse.”


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