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5.56 vs .223 Rem.

Discussion in 'General Gun Discussions' started by Oldhandloader, Aug 2, 2018.

  1. Oldhandloader

    Oldhandloader Member

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    Having an ongoing friendly discussion about all the warnings of not shooting 5.56 in a 223 chambered rifle.
    Has anyone out there got a reportable case of injury or damage to the gun / shooter of using the 5.56 in a .223 ?
    Thanks and please advise.

    Old Handloader
     
  2. GunnyUSMC

    GunnyUSMC Member

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    I’ve never heard of a firearm being damaged or shooter being injured, but that’s not to say that it has never happened.
    5.56 is most often loaded at a higher pressure then 223. The extra freebore and throat allows 5.56 to handle the higher pressure safely.
    Most people can’t tell you what the difference between the two chambers so, here’s a pic that will make it clear.
    5D53BC5F-CDE7-433D-A1F2-E7D0D33B0CCB.png
     
  3. Tommygunn

    Tommygunn Member

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    In addition to what GunnyUSMC said, there may be occasional confusion in how manufacturers mark their guns. The Ruger Mini 14 for example, has .223 marked on the barrel, but can handle 5.56mm. ammo. The chamber is milled to 5.56 specs in spite of the markings.
    If there is any doubt about whether a rifle can handle 5.56, CONSULT THE MANUFACTURER.
    I've seen bolt .223 rifles marked that, and heard that 5.56mm. is verboten, but I don't know which specific brands this applies to.
    Again, I don't know any .223 guns that have detonated, but I would use caution, and KNOW what your gun will chamber safely!
     
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  4. alsaqr

    alsaqr Member

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    Since 1966-68 i've fired hundreds of thousands of rounds of M193 ball ammo in .223 rifle chambers with no ill effect to me or the rifle. No popped primers, no nothing.

    Contrary to popular opinion most .223/5.56mm barrels are not rifled by gunsmiths. It's done by day labor. Chamber dimensions can be all over the place.

    Lucky Gunner tested military ammunition in .223 chambers:

    https://www.luckygunner.com/labs/5-56-vs-223/

    There is another problem with the US made 5.56mm military ammunition sold today. Many of those cases have very long necks: If that long neck gets rammed into the forcing cone pressure could skyrocket. Used to reload about ten thousand US 5.56mm cases every year. Now its more like 3,000.

    If you don't feed good about firing 5.56mm ammo in a .223 chamber then don't do it.
     
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  5. MistWolf

    MistWolf Member

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    Gunny, that's like saying "The 30-06 is loaded to higher pressures than the 308. The extra case capacity allows the 30-06 to handle the higher pressure safely." The extra freebore of the 5.56 is really extra case capacity. It allows more powder to be used to achieve higher velocities at the same pressure levels.
     
  6. Hokie_PhD

    Hokie_PhD Member

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    Can you provide a source to support this claim?
    I ask as it seems very far fetched that in such a highly regulated industry and firearms that a company would be willing to use day labor. Maybe I’m missing something, but machinist are now what are being called grey collar labor. Jobs that aren’t white collar but require much more education, skill, and knowledge than blue collar. So I’m really interested in hearing where you got this info.
     
  7. alsaqr

    alsaqr Member

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    Reaming rifle chambers ain't rock science and no machinist is required. i sometimes ream my own chambers.

    While working a jobsite in MA i sometimes ate breakfast with folks who worked at a firearms manufacturing company. The workers, including those who reamed the chambers, were day labor. That company was famous for out of spec chambers. They also re-ground dull reamers.

    Lucky Gunner says:

    "You’re getting one that is, if it was manufactured by a reputable company, somewhere within the range of acceptable tolerances for a .223 Remington chamber. If it was made by a company with more of an emphasis on cost savings than exact machining, it could be a minimum spec .223 chamber, or something that is closer to 5.56, or anywhere in between. Even between chambers reamed by a reputable company, differences exist, as you will see."
     
  8. jmr40

    jmr40 Member

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    Actually most 308 is loaded to higher pressure than 30-06. But the 30-06 is a good analogy I'll touch on shortly.

    5.56 marked ammo CAN be loaded to slightly higher pressure than is allowed in 223. That doesn't mean much, or any, actually is. You'll find very few factory loads in any chambering loaded right to max. That is something usually done by handloaders pushing the envelope.

    The 30-06 began life in 1903 and was loaded to much lower pressures than today. In WW-1 military 30-06 loads pushed a 150 gr bullet to 2700 fps. By WW-2 that was increased to 2800 fps and the Garand is designed to work at those pressure levels. Today typical factory loads push a 150 gr bullet to 2900-3000 fps and there are a few as fast as 3100 fps.

    The 308 was developed to match the 150/2800 spec from a smaller capacity case, but operating at higher pressure.

    The 223/5.56 took a similar path as 30-06 but the higher pressure 5.56 load was given a different name. 30-06 is loaded to at least 4 different pressure levels with a far greater variance than between 223 and 5.56. Yet we don't have 4 different names for 30-06.

    You also see great differences in the tolerances between how champers are cut. Manufacturers start out with a new chamber cutter and the 1st few barrels made with it will be larger than the last few chambers cut with that tool because the tool wears down with use. Once the tool gets worn to a certain point the tool is discarded and a new one installed. Custom barrel makers pay closer attention to this and change tools sooner and will have closer tolerances in their barrels.

    Getting back to the 30-06 analogy. Because of the wide range of loads available for 30-06, and the differences in tolerances among factory barrels it isn't uncommon at all to have issues with SOME ammo, in SOME rifles. In fact we see this far more often than issues with 223 and 5.56.

    Realistically the biggest problem would be firing higher pressure 5.56 ammo in a semi-auto designed to operate at 223 pressure. Which is one of the biggest issues with 30-06. Most of the modern high pressure loads don't function in semi-auto 30-06 rifles. But I don't think I've ever seen a semi auto rifle with a 223 chamber.

    In a bolt gun chambered in 223 you'd have to get one with a chamber cut to the minimum, and load a 5.56 round loaded near max levels to see issues. But this isn't uncommon with any cartridge.
     
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  9. TheVision

    TheVision Member

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    That is not correct. M1 ball, circa 1926, was a 172 grain boat tail projectile at 2700 FPS. M2 ball, a 150 grain flat base projectile at 2800 FPS, was down-loaded in 1938 to prevent overshooting the impact area of National Guard ranges.

    The M1 can work with M1 ball pressures.
     
  10. GunnyUSMC

    GunnyUSMC Member

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    You see, you just explained it pretty much with out realizing it. The 5.56 and the 223 cases are pretty much the same. Most 5.56 have thicker walls. They both have the same overall length. The longer freeborn and throat really isn’t like extra case capacity due to the fact that they are in front on the bullet. When the round is fired, the pressure spikes when the bullet goes past the freebore and throat into the bore. With the 223 this happens sooner then the 5.56.
    The advantage to the 5.56 chamber is that it will handle the higher pressure ammo better, but at a cost to accuracy. This is because the bullet has a bigger jump from the case mouth to the bore.
    Now in a bolt action rifle it’s not as much an issue as in simi autos. I have a Winchester Mod. 70 in 223 that I’ve fired plenty of 5.56 in. But the the 5.56 loads are light compared to my hand loads for groundhog hunting.
     
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  11. Slamfire

    Slamfire Member

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    The current military 5.56 specifications have done dark on DoDiss. You can look at the older ones, but the US Army prefers that no one sees or understands what they are doing. I think it makes it easier for them to do stupid things and be unaccountable. However, mud slinging aside, the US Army is free to raise pressures as much as it wants, crack as many bolt lugs as it wants, wear out as many rifles as it wants. All on the taxpayer dollar. Based on what I have read, that is exactly what they are doing. Someone else can research the round, but the last environmentally friendly round the developed, they bumped the pressure up again. Pressure information not released to the public. But word got out, Army bumped up the pressures again. I think the primary reason is that the 5.56 round is not as effective as they want in a 16" barrel. So the Army Ordnance buggers just bump the pressures up, taxpayer pays for the worn out weapons, the troops have to deal with the jams.

    As an example of the gross overloading they do, I listened to a Car Talk program and some GI's called from Iraqi. The ball joints on their HMMWV;'s were wearing out in three weeks and the guys wanted to know if there was a special grease that would make the ball joints last longer. Tom and Ray were flummoxed, ball joints should last 100,000's of miles, ball joints wearing out in three weeks is most unusual. Except, as it turns out, if you are loading your HMMWV 17,000 lbs over gross vehicle weight. Then it becomes understandable, and there was not any grease out there that could fix that problem.

    So, you load military 5.56 in your civilian rifle, what makes you think that your military round is not one of those 17,000 lbs over gross vehicle weight rounds? Someday, it might be.
     
    Last edited: Aug 4, 2018
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  12. alsaqr

    alsaqr Member

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    Yep, they boosted the pressure in order to get a decent velocity from the 16" and 10.3" barrels.

    Read The Godfather's Return in the July issue of Guns and Ammo magazine by Tom Beckstrand. Tom Beckstrand talked with Jim Sullivan, Gene Stoner's assistant in the design of the AR-15 rifle. Jim Sullivan is the reason the gas system sits on top of the barrel.

    Surefire, maker of suppressors for SOCOM rifles, asked Mr. Sullivan to conduct a "sanity check" on the changes the Army has made to the M16 type rifles. Mr. Sullivan recently redesigned the bolt carrier and added a reciprocating weight to "delay" cycling and improve longevity.

    Beckstrand says M855A1 ammo develops 64,000 pounds per square inch. That ammunition is very hard on rifles.
     
    Last edited: Aug 3, 2018
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  13. GunnyUSMC

    GunnyUSMC Member

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    I wouldn't want to shoot M855A1 in any of my AR's. But I would't mind getting my hands on some to pull and reload.
     
  14. cougar1717

    cougar1717 Member

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    Several years ago, while working up a 223Rem handload, I noticed that Ramshot TAC had data for both 223 and 5.56. With my newfound real estate of higher max charges for published data, I felt compelled to work up to the absolute max of TAC's 223 data (which is midrange data for 5.56 per Ramshot's data). After trying out part of the workup loads with one AR and getting mediocre results, it made sense to doublecheck with a second AR. Needless to say, I only remembered that the second AR was chambered in 223Rem (not wylde or 5.56) AFTER I picked up the five empties that were missing some primers. No harm, no foul - but that brass went directly into the recycling bin.
     
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  15. taliv

    taliv Moderator

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    ask ned christiansen
     
  16. Slamfire

    Slamfire Member

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    That should cause a lot of failures to extract. The proof pressures on 5.56 ammunition used to be a 70 K psia round and, the weapon was designed around a 50 Kpsia round. Those are CUP numbers, but in the day, 1 CUP was assumed to be 1 lb pressure. Anyway, a 64 K psia round is only going to go up in pressure as temperatures climb, if the ammunition is left out in the sun, and as the weapon heats up.

    These insane pressures are inappropriate for a combat weapon. The very best military rounds, such as the 30-06, 303 Brit, 7.62 X 39, the Chinese service round, all operate in the 40 kpsia region, which allows margin for heat. These insanely high pressures for M88A1 ammunition, a combat round, only shows what a bunch of paper pushing clowns we have in the Army Ordnance Bureau. I predict more stories of jams, broken weapons, will be forthcoming out of combat zones. Assuming the Army does not classify them Top Secret, just as they did when they fielded the M16 in the Vietnam War. Lots of good American boys died with jammed M16's in their hands. There are whole books on that time period.
     
  17. silicosys4

    silicosys4 Member

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    30-06: 60kpsi
    .308: 62kpsi
    .303: 49kpsi
    7.62x39: 45kpsi

    http://www.lasc.us/SAAMIMaxPressure.htm
     
  18. greg_r

    greg_r Member

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    Relying on published pressures for the 5.56x45 NATO and the 223 Remington can not be done. The 223 is a SAAMI round and the NATO is...well...a NATO round. SAAMI and NATO measure pressures differently and results are not the same.

    I am sure there are some figures somewhere where the two cartridges were tested in the same chamber using the same pressure testing device, but I do not know where they are.

    The biggest difference between dimensions in not the case, but the chamber. The 5.56 has a longer larger leade. A 223 has to make a longer jump to reach the rifling and there is a chance the bullet could become off centered during that jump causing accuracy issues. There have been several attempts to make a hybrid chamber and the 223 Wylde is the most popular of those efforts. The Wylde chamber combines the long leade of the 5.56 and the tighter diameter of the 223.

    I believe the Wylde is the best of the best of the compromise chambers and will not buy a barrel with any other chamber. I have a 223 Remington, my first And a 5.56, my first AR. I have 3 other 223 AR builds, a varmint, a sporter, and a pistol. They are all chambered 223 Wylde.

    Here is an excerpt from an article talking about this.

    "The organization known as SAAMI or the Sporting Arms and Ammunition Manufacturers’ Institute, sets industry standards for ammunition, firearms and components. SAAMI has standardized the .223 but not the 5.56. The 5.56 standards are set by the military, and because the two rounds have different organizations standardizing them, pressures are measured differently between the two. Since pressure is measured differently, it is not possible to make a comparison. Instead you would be required to test both using the same chamber, and methods to see differences. As a general consensus, 5.56 may be loaded to higher pressures than .223."

    And a link to the article.
    http://blog.adamsarms.net/blog/223-vs-556
     
  19. RecoilRob

    RecoilRob Member

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    Thank You!:) I too have reloaded thousands of LC 5.56 and by gum every single one of them was WAY long...like .025+ and I don't think it's coincidental that cutting them back to the normal .223 length removed pretty much all of what had been crimped. If you get ammo like this with the long neck crimped tightly into the cannelure, it must have somewhere to go to release the bullet or the pressures will naturally go skyward. Unless you have a rifle with 'Match' chambering I think most manufacturers will err on the side of caution and leave the throat a bit on the long side even in .223...just in case. But never say never so if you're not sure about the chamber or ammo match...check.
     
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  20. alsaqr

    alsaqr Member

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  21. silicosys4

    silicosys4 Member

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    Its been a long time since a 50kpsi 30-06 M2 round was fired by the U.S. Military.. Regarding your link, I would love to verify your statement about M80 pressures, but I'm not going to search through a 325 page pdf to find the relevant line.

    I guess I should have stated my point; 64kpsi is not an "insanely high pressure" round, if you compare with what else is out there. There are quiet a few rounds out there with higher working pressures.
     
    Last edited: Aug 4, 2018
  22. 250-3000

    250-3000 Member

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    My 223 M77 thankfully would not allow the bolt to close.
     
  23. JohnKSa

    JohnKSa Moderator Staff Member

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    This would be unlikely as the mismatch is not severe.

    Based on various sources, it usually (though not always) takes more than just the chamber mismatch itself to cause a problem. So the mismatch in addition to something like shooting in very hot conditions, or perhaps with a gun that has gotten pretty dirty, is likely to cause a problem but the mismatch alone might not. The most severe symptoms will probably be popped primers and extraction issues. Neither is likely to injure the shooter or damage the gun but either could create a malfunction that is difficult to clear.

    This topic is complicated by a number of factors:

    • Not all .223 firearms really have a .223 chamber. This means that much of the "evidence" that the mismatch never causes a problem comes from situations that don't actually involve a mismatch.
    • Not all 5.56 ammo is loaded to near maximum 5.56 specs. Given that the mismatch doesn't cause a tremendous pressure increase, the mismatch on top of lightly loaded 5.56 isn't likely to cause any problems.
    • The mismatch isn't severe enough to reliably cause problems and that seems to be very difficult for some people to understand. If it doesn't cause a problem each and every time the trigger is pulled on a mismatch, there are people who believe that it can NEVER cause a problem.
    • A lot of people apparently REALLY want to shoot 5.56 ammo in .223 guns and that desire is strong enough to motivate them to almost fanatically promote their point of view and to attack any dissenting evidence.
     
  24. Slamfire

    Slamfire Member

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    Posters quoting SAAMI spec maximums for average pressures of issued military ammunition, don't know what was out in the field. The pressure limits for the 30-06 were set prior to WW1. Powder technology improved so much that if you look at the historical record, or put it this way, find an example of the 50,000 psia military 30-06 cartridge. One older shooter I met, he loaded ammunition at Badger Army Ammunition plant. He actually determined the amount of powder in the case, measured velocity, measured pressure. The WC852 he used, produced the desired velocity, and the pressures were so low, that as he said "we loaded for velocity". He never ever had to worry about exceeding the cartridge pressure limits.

    And that is all to the good. What is lacking from all the clever quotes of SAMMI maximum documents is an understanding that if you can do the same job at lower pressures, you are better off doing that job, at lower pressures. Some drivers never figure out why their engine smokes, and that it is somehow related to the burn outs they do between each and every traffic light. Military ammunition is not treated with kid gloves, it gets bounced around, cooked in containers, cooked in the sun, sometimes the troops have to use the stuff in very hot, nasty places. And, they have to shoot until the enemy goes away, and that might mean some hot weapons. High initial pressures only create real problems for the troops. Lots of good American boys died in Vietnam due to the Army Ordnance Bureau bumping up the pressures in the cartridges of the era. Their M16's jammed. Dead Troopers and cash awards for the Army Ordnance Civilians back home, that's what you call American Justice. Jams are not an academic issue when you have a AK bayonet in your chest.

    The Chinese 5.8 X 42 mm is operating 36,980 to 41,970 psi per Wiki. I think the Chinese had some real professionals determine their cartridge requirements. You know, American Universities graduate more Chinese PhD candidates, in Science and Engineering, than CONUS born Americans. Maybe the US Army Ordnance Bureau needs to hire some smart Chinese Engineers! You know, guys who can not only add and subtract, but won't drool or fall asleep in meetings.

    I got to talk to Korean War veterans, and a few WW2 veterans, they never ever had the sort of jams, mis feeds, malfunctions that become common once the M16 was adopted. The Garand was extremely reliable, every where. The thing was used in the Aleutians, the Middle East, and in the jungles.

    As for the M14, I found even fewer Vietnam veterans who used the thing, but it was extremely reliable, and guys who had it, tried to keep them, because the first M16's were POS. I found some early M118 data, the stuff was running lower 40 kpsia with ball powder.

    The 303 Brit MKVII round was 39,000 psia max, machine gun cartridges were bumped up, but the rifle ammunition was nice and sensibly low pressure.
     
    Last edited: Aug 4, 2018
  25. GunnyUSMC

    GunnyUSMC Member

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    I think we’ve gotten a little off topic. The OP was asking about thr difference between 223 and 5.56 and if anyone knew of any injuries or weapons damage from shooting 5.56 in 223 Firearms.
     
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