every manufacturer and oversight body that deals with ammunition and firearms manufacturing will not back the usage of 5.56 in 223 chambers. it may not be an issue in those billions of rounds you claim, but if it is, no one is going to back it when it comes to legalities and the subsequent lawsuits. plus if it ends up being an injury issue, is it really worth using it?
.223 remington versus 5.56 x 45 mm NATO - is it safe to interchange???
- Thread starter Boltgun
- Start date
Blastattack
CGN Ultra frequent flyer
- Location
- Winnipeg MB
Every single oversight body? There are two, CIP and SAAMI, and CIP does not distinguish between them. So 50% of the oversight bodies don’t agree with you. Citing what lawyers do to cover their asses is really a baseless argument as they will weasel in as much as they can, usually without basis. Remember if you sign up for Disney plus, Disney can kill you and you can’t sue them! Please provide at least one example where a .223/5.56 “mix up” has resulted in legally actionable problems. Considering the billions of rounds and millions of firearms, you should be able to find at least one substantiated forum post that supports the notion that this is a problem.
SAAMI and CIP don't set pressure limits for 5.56, NATO and Military standards do. SAAMI, has a standard but its measured their way whereas NATO measures it a different way.
the chances of injury are low, from an overpressure event in firing 5.56 in a .223 chamber.
https://www.luckygunner.com/labs/5-56-vs-223/
https://bulletin.accurateshooter.com/2022/07/223-rem-vs-5-56x45mm-nato-what-you-need-to-know/
no I do not have any anecdotes. I do rely on the engineering and manufacturer recommendations for the most part though.
https://saami.org/faqs/#ammunition-firearm-chambered
https://www.hornadyle.com/resources...rence-between-556-nato-and-223-rem-ammunition
https://www.remington.com/big-green-blog/caliber-crackdown-223-vs-556.html
Like LG mentioned in his article, the majority of issue likely to be found are popped primers in the action. Given the manufacturing differences, I lean on the side of caution and purposefully don't use 5.56 in .223. And regardless of the lack of anecdotal evidence, there is enough engineering warning out there, that if there should be injury that resulted, one would have little to stand on in a civil suit.
so go ahead, enjoy your 5.56 in your .223 gun all you want. in the end it on you the individual.
best I can give you is these:
https://uniquetek.com/saami-drawings go to the .223 to open it or
https://saami.org/technical-information/ansi-saami-standards/
SAAMI Z299.4 – 2015 and scroll down to the 223 remington page (80 of 375)
https://bobp.cip-bobp.org/en/tdcc_public?autocomplete_homologation_filters[cartridge_id]=5.56x45mm scroll down to the 223 remington line and click on the english TDCC link for the chamber drawing.
- Location
- Port Edward BC
I bought a CZ .233 REM and a crate of 5.56 looking forward to doing some shooting. Fired off a mag and the target looked like I had fired a shotgun at it. I was reloading and noticed a case on the bench that looked odd, when I looked at it I saw that the case was split. Four out of the five rounds had split cases, so much for shooting that day. Took the rifle to a gunsmith as I was worried I may have damaged the chamber which turned out it wasn’t. Never shot 5.56 NATO in a .223 REM chamber again.
Dude, this old wives tale that "everybody knows" will NEVER die. There are WAY too many people who will accept silly ideas without question for an idea like this to die.
redshooter
CGN Ultra frequent flyer
- Location
- Central Ontario
It's not an old wives tale, it's about the chamber.
It's very unlikely you'll have a problem, UNLESS you have a short throat, and long/seated long projectiles, then you might get some pressure issues, if you do don't shoot that ammo.
I consider 5.56/223 interchangeable, BUT I don't own an older 1 in 12, 1 in 14 varmint gun, or a custom with a really tight chamber, if I did, I likely wouldn't be shooting 62gr/55gr 5.56x45 because it likely wouldn't shoot for ####, pressure signs, or not.
New rifle, and want to shoot 5.56 through it, fine, go buy 20 PMC 5.56 in the bullet weight you want to shoot, and try them, no pressure signs, you're golden, go buy a case.
As for the split necks, that's not due to you shooting "5.56" in a CZ, hard brass is usually the cause of that.
It's very unlikely you'll have a problem, UNLESS you have a short throat, and long/seated long projectiles, then you might get some pressure issues, if you do don't shoot that ammo.
I consider 5.56/223 interchangeable, BUT I don't own an older 1 in 12, 1 in 14 varmint gun, or a custom with a really tight chamber, if I did, I likely wouldn't be shooting 62gr/55gr 5.56x45 because it likely wouldn't shoot for ####, pressure signs, or not.
New rifle, and want to shoot 5.56 through it, fine, go buy 20 PMC 5.56 in the bullet weight you want to shoot, and try them, no pressure signs, you're golden, go buy a case.
As for the split necks, that's not due to you shooting "5.56" in a CZ, hard brass is usually the cause of that.
- Location
- Port Edward BC
My cases were split from about an 1/4 of an inch above the base for about an inch. Necks were fine.
Blastattack
CGN Ultra frequent flyer
- Location
- Winnipeg MB
Sounds like junk ammo. You said Crate and not Case or Can, so I am assuming it’s that Chinese stuff.
- Location
- Port Edward BC
Ok case. To be more exact a wooden case. The kind that was on the floors of outdoor shops years ago on pallets. The wooden boxes, crates, cases had the handles on the sides. The kind of ammo that hundreds of 5.56 owners shot without any problem. You should actually catch up with the topic at hand instead of assuming so much. It would make more sense to you.
Blastattack
CGN Ultra frequent flyer
- Location
- Winnipeg MB
So it was the Chinese stuff. Not exactly stellar quality. A friend had some and used it in his Type 97. It was pushing 3400fps and we had a spectacular failure where it split around the whole circumference 1/4” beneath the shoulder, and rammed a fresh round into the remaining case, ejecting the rear end of the case, and looked like a .38 super.
redshooter
CGN Ultra frequent flyer
- Location
- Central Ontario
Regardless it wasn't because you shot 5.56x45 in your CZ. Try some PMC 55 gr FMJ X-Tac, it's a bit spicier than their 55 gr FMJ Bronze load, 70 fps faster in a 20" vs 24" barrel. I've got $20 that says you won't have any pressure signs, assuming that CZ has a 1 in 9 twist barrel, or faster.
- Location
- Port Edward BC
I don’t have the rifle anymore. It was a 527 with 1:12 twist.
There was no problems with .223 REM ammo.
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redshooter
CGN Ultra frequent flyer
- Location
- Central Ontario
As already pointed out, your problem was 99.9% the brand, not that it was 5.56X45, case size is identical, zero difference. The difference between the two isn't enough to cause cases to fail if in spec.
- Location
- Port Edward BC
The case size may be the same but other dimensions are different. A .223 REM chamber is not recommended to be fed a steady diet of 5.56x45 yet a Wylde chamber will safely fire the NATO round. The NATO round operates under higher pressures. There is differences.
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redshooter
CGN Ultra frequent flyer
- Location
- Central Ontario
Pretty clear I get that...
The throat, that's the difference, NATO chamber has a longer throat, that's the only difference, the higher pressure (as a problem) being from a long bullet in a short throat, because the higher pressure won't cause any trouble BUT in the above situation...or you have junk ammo, which is clearly the case, because if it was just due to it being 5.56 in a modern rifle the worst you'd get is a popped primer, or sticky case extraction.
I suspect that is why SAAMI issued the warning. Variations in gunsmithing/barrel-firearm manufacturing/ammo manufacturing, etc. given the right circumstances, if the tolerance stacking lines up, then you can have a pressure event. Albeit rare, if you encounter a gun with bad heat treat or incorrect specs, then you have recipe for a failure. in the end, people choose to do what they do and if there is a failure and a gun is damaged, the ammo/gun combo will invalidate any real or perceived warranty.
