As ARlady had brought up in a previous thread, there are some differences between 5.56 and .223 chambered ammunition.  In tryin to keep with safe shooting procedures, which AR-15 models have 5.56 chambers, and which have .223 chambers?

Your answer should be marked on the BARREL.
HUNTER FROM ARGENTINA
OUT.

Hunter is correct , its marked on the barrel just ahead of the front site assembly , along with twist rate .

Not always true. Olys are marked 5.56mm on the barrel and they have SAAMI spec chambers. FWIW, I've shot thousands of rounds of military surplus ball and commercial ammo through my Oly without any problems. Maybe I got one of those rare Mil-Spec SAAMI chambers.

The actual SAAMI recommendation is not use 556 mil ammo in a 223 chamber......apparently...some of the mfg`s bypass....example...armalite 180b..advertised with 223/556 cal. ......a little confusion anyone?.........................(apparently..the best thing to do is stay away from surplus ammo?)

Quoted: Your answer should be marked on the BARREL. HUNTER FROM ARGENTINA OUT.

uh, gee, guys, that would be just damn peachy if we had every AR15 rifle in our collection.  we don't.

the whole point of the question was which manufacturers have .223 or 5.56 stamped on the rifle.

fwiw, i just check the bushmaster and colt.  not on the barrel.  intstead it's stamped onto the lower.  bushmaster says "Cal .223-5.56mm".  and the colt says .223 only.

so here's the point Matt_S was getting at, i think.  it's fairly obvious some of the rifles are chambered in .223.  yet you've been telling us that we shouldn't shoot 5.56 through .223 chambers.  now how many guys do you think have run some 5.56 surplus through their ".223" rifles?

hence, the conundrum.  personally, it would seem to me that the manufacturers would make a big deal out of making sure the owners didn't fire one out of the other if they shouldn't.  and yet, that doesn't seem to be the case, does it?

so what's the real scoop?

I think Big Bear answered the question.....check some of the links where guys are testing different ammo types.....and most..if not all the ads for ar`s state 223/556.....one thing is..223 ammo (commercial) just is not that expensive...personally, I am of a mindset that since I paid good money for my armalite...I`m not going to cheapo out on ammo..when I can get decent stuff for about $3.00 a box...or thereabouts.....BUT...what if somebody gives me a few boxes of mil ammo?....sure I`m gonna use it........

Quoted: Quoted: Your answer should be marked on the BARREL. HUNTER FROM ARGENTINA OUT. uh, gee, guys, that would be just damn peachy if we had every AR15 rifle in our collection.  we don't. the whole point of the question was which manufacturers have .223 or 5.56 stamped on the rifle. fwiw, i just check the bushmaster and colt.  not on the barrel.  intstead it's stamped onto the lower.  bushmaster says "Cal .223-5.56mm".  and the colt says .223 only. so here's the point Matt_S was getting at, i think.  it's fairly obvious some of the rifles are chambered in .223.  yet you've been telling us that we shouldn't shoot 5.56 through .223 chambers.  now how many guys do you think have run some 5.56 surplus through their ".223" rifles? hence, the conundrum.  personally, it would seem to me that the manufacturers would make a big deal out of making sure the owners didn't fire one out of the other if they shouldn't.  and yet, that doesn't seem to be the case, does it? so what's the real scoop?

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Quoted:
Your answer should be marked on the BARREL.
HUNTER FROM ARGENTINA
OUT.
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uh, gee, guys, that would be just damn peachy if we had every AR15 rifle in our collection. we don't.

the whole point of the question was which manufacturers have .223 or 5.56 stamped on the rifle.

fwiw, i just check the bushmaster and colt. not on the barrel. intstead it's stamped onto the lower. bushmaster says "Cal .223-5.56mm". and the colt says .223 only.

so here's the point Matt_S was getting at, i think. it's fairly obvious some of the rifles are chambered in .223. yet you've been telling us that we shouldn't shoot 5.56 through .223 chambers. now how many guys do you think have run some 5.56 surplus through their ".223" rifles?

hence, the conundrum. personally, it would seem to me that the manufacturers would make a big deal out of making sure the owners didn't fire one out of the other if they shouldn't. and yet, that doesn't seem to be the case, does it?

so what's the real scoop?





uh, geeeeeeee GIRL, that's why i REMARKED BARREL in caps and BLACK color, hell you could be even firing 12,7 (.50)ammo using a .223/5.56mm marked LOWER. My whole point is that IF 5.56 is marked on the B A R R E Lthen you shouldn't have any problems using 5.56 ammo, if it's NOT, then i'd just stick to .223 commercial stuff.
i hope that was clear enough
HUNTER FROM ARGENTINA
OUT.

Bushmaster marks on the barrel AND on the lower receiver.  Never go by the lower's markings - especially as I've seen 9mm OLYs with lowers marked .223.

Want to know who has what?  Why not visit here: communities.msn.com/TheMarylandAR15ShootersSite/ar15brands.msnw

Quoted: Bushmaster marks on the barrel AND on the lower receiver.  Never go by the lower's markings - especially as I've seen 9mm OLYs with lowers marked .223. Want to know who has what?  Why not visit here: communities.msn.com/TheMarylandAR15ShootersSite/ar15brands.msnw

EXACTLY!!!!!
HFA
OUT.

My new Bushmaster XM15-E2S barrel is marked
B MP 5.56 NATO 1/9 HBAR,

but the receiver shows Cal 223-5.56MM

The new Bushmaster Varminter is however advertised as having a barrel made to SAAMI specs.

My 3 month old OLY has 5.56 stamped on the barrel and XM193 runs 3375fps out of it (20 inch ).
I am not to concerned about whether or not it is a Saami or mil-spec chamber with that velocity.
It feeds the stuff without a hitch.

Lee

you still don't get it do you?  it doesn't matter where the fuck the marking is, if i don't have a particular manufacturer's barrel in front of me, i still have no way of knowing whether it's chambered for 5.56 or .223.

THAT is the question Matt_S was asking:  which caliber matches with which manufacturer.

thank you, Forest for the link.  at least somebody is trying to answer the question.

btw, i did find it on the barrel after i looked in better light.

I'm no expert by any means.  But I have and will continue to shoot .223Rem and 5.56Nato out of my AR15 and never worry about it for a second.  The diferances just aint that big a deal.

Now if you really want to go nuts I'll ask you this.  What should I shoot out of my Mak90....it's marked 5.56x45!!

Sgtar15

Guy's,and Lady.
There is only one way to determine what chamber dimensions are on ANY rifle.
Chamber casting with Cerrosafe.
If that is not to your liking,get a set of Headspace gauges and have at it.
Make sure to get "Go"-"No go" and "Field".
They cost a bit up front,but will save you a headache or two over a lifetime.Especially if ya buy a barreled upper at a Gunshow or from "Some guy".
For the record,.223 Gauges will show excessive headspace in a 5.56 chamber and close on a .223 "Field" gauge.
My experience has been that both Colt and Bushmaster both have 5.56 Nato chambers.
The rest is a mixed bag and vary.
As to trusting what is marked on the barrel that is also a bad thing.
I once picked up a Barrel assembly at a Gunshow that was marked "5.56 Nato".When I got home and did a chamber casting,it was in fact not only NOT 5.56,it wasn't .223!! It was some fuzzy knock off that was short chambered,and very poorly done to boot!
I called it 50 bucks worth of education and now carry the gauges and intended bolt with me,if I plan on buying a barrel.
As to the issue of 5.56 in a .223 chamber.
Yes you CAN get away with it.
Just keep in mind that there are two different dimensions involved,and both are subject to working tolerences in mass production.
If a Grasshopper farts in a jungle in Brazil,and that causes a butterfly to take flight and it lands on the knob at the factory in Greece...
Where do you want to be when the tolerances stack against you?
If nothing else just PLEASE wear your eye protection when shooting.
KB's are NOT pretty,and get uglier when they affect flesh.
Be safe folks!
S-28
P.S.
If you ever do a chamber cast of a Mini-14 you will find tolerences on the outside edge of SAAMI spec.That's how folks get away with it,and Bill Ruger can shrug it off.
Cheers!
S-28

Found this, it might help:

http://www.fulton-armory.com/556-vs-223-Chambers.htm

Summary, its not safe to shoot NATO 5.56 in a .223 chambered barrel.  It is safe to shoot .223 in a NATO 5.56 barrel on the other hand.

Quoted: you still don't get it do you?  it doesn't matter where the fuck the marking is, if i don't have a particular manufacturer's barrel in front of me, i still have no way of knowing whether it's chambered for 5.56 or .223. THAT is the question Matt_S was asking:  which caliber matches with which manufacturer. thank you, Forest for the link.  at least somebody is trying to answer the question. btw, i did find it on the barrel after i looked in better light.

Are you sexy when you get angry?  

(Sorry I had to ask!)

Quoted: you still don't get it do you?  it doesn't matter where the fuck the marking is, if i don't have a particular manufacturer's barrel in front of me, i still have no way of knowing whether it's chambered for 5.56 or .223. THAT is the question Matt_S was asking:  which caliber matches with which manufacturer. thank you, Forest for the link.  at least somebody is trying to answer the question. btw, i did find it on the barrel after i looked in better light.

haha WOW somebody woke up in a BAD MOOD today, don't take it too personatly Lady, i just missunderstood Matt_S's question, that's all.
HUNTER FROM ARGENTINA
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Okay guys, I appreciate all the conversation here and I sure as heck wasn't trying to start a fight.  That is ARlady's specialty....obviously.  I think I have been working her too hard trying to get this house sold.  I mean I didn't even give her time to decorate it.  That is twice now where I moved and stayed less than a year so i best get my butt in gear before she REALLY gets upset.


My question was more directed to, if I buy an off the shelf Armalite it will have  .223 or 5.56 chamber?    Same goes for Bushmaster, which I know is 5.56 since I checked the BARREL .  I also know my Colt has a .223 chamber.

I know Olympic Arms from Big Bears post has  a .223 chamber. I was just trying to see who, if anyone else put things out with the 5.56 chamber if I just wanted to be safe.

I am sorry for the confusion that I had caused.

Well I do not know if this is "Food For Thought" or "Fuel To The Fire". This is what I have received from the SAAMI on this 5.56mm/.223Rem. subject.
BTW. I have and will continue to shoot military 5.56mm ammunition in guns chambered for .223 Rem. but I do accept all responsibilty for my actions on shooting it. I have never seen any adverse problems from do such.

.223 Rem.  VS.  5.56mm

There are a lot of questions about these two cartridges. Many people think they are identical – merely different designations for commercial and military. The truth is that, although somewhat similar, they are not the same and you should know the differences before buying either cartridge.

The cartridge casings for both calibers have basically the same length and exterior dimensions.

The 5.56 round, loaded to Military Specification, typically has higher velocity
And chamber pressure the .223 Rem.

The 5.56 cartridge case may have thicker walls, and a thicker head, for extra
Strength. This better contains the higher pressure. However, a thicker case
Reduces powder capacity, which is of concern to a reloader.

The 5.56 and .223 Rem. Chambers are nearly identical. The difference is in the “Leade”. Leade is defined as the portion of the barrel directly in front of the chamber where the rifling has been conically removed to allow room for  
the seated bullet. It is also more commonly known as the throat.  Leade in a .223 Rem. chamber is usually .085”. In a 5.56 chamber the leade is typically .162”, or almost twice as much as in the .223 Rem. chamber.

You can fire .223 Rem. cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity over firing the .223 round in the chamber with the shorter leade it was designed for.

Problems may occur when firing the higher-pressure 5.56mm cartridges in a .223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads and gun functioning issues.

The 5.56mm military cartridge fired in a .223 Rem. chamber is considered by SAAMI (Small Arm and Ammunition Manufactures Institute) to be an unsafe ammunition combination.


Before buying either of these two types of ammunition, always check your gun to find what caliber it is chambered for, then buy the appropriate ammunition. Most
5.56mm rounds made have full metal jacket bullets. Performance bullets – soft points, hollow points, Ballistic Silvertips, etc. – are loaded in .223 Rem cartridges. Firing a .223 Rem. cartridge in a 5.56mm chambered gun is safe and merely gives you a slightly reduced velocity and accuracy. However we do not recommend, nor does SAAMI recommend, firing a 5.56mm cartridge in a gun chambered for the .223 Re. As the shorter leade can cause pressure-related problems.


Winchester Law Enforcement Ammunition
East Alton Illinois

Quoted: Okay guys, I appreciate all the conversation here and I sure as heck wasn't trying to start a fight.  That is ARlady's specialty....obviously.  I think I have been working her too hard trying to get this house sold.  I mean I didn't even give her time to decorate it.  That is twice now where I moved and stayed less than a year so i best get my butt in gear before she REALLY gets upset. My question was more directed to, if I buy an off the shelf Armalite it will have  .223 or 5.56 chamber?    Same goes for Bushmaster, which I know is 5.56 since I checked the BARREL .  I also know my Colt has a .223 chamber. I know Olympic Arms from Big Bears post has  a .223 chamber. I was just trying to see who, if anyone else put things out with the 5.56 chamber if I just wanted to be safe. I am sorry for the confusion that I had caused.

Lady seems to me that Y O U were the one who did NOT get it.....oh well, sometimes hormones can be tricky :), nevermind like you guys say 'water under the brigde'.
(i know she's not gonna  like that comment :)

Matt_s:
COLT B A R R E L S ARE chambered in 5.56 not in .223, with the exception of some bull barreled match rifles, MAYBE.
HUNTER FROM ARGENTINA
OUT.
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Quoted: I know Olympic Arms from Big Bears post has  a .223 chamber. I was just trying to see who, if anyone else put things out with the 5.56 chamber if I just wanted to be safe.

FYI, Olympic Arms switched to military chambers in their chrome moly barrels in June 2001. SUM chambers remain SAAMI spec. Oly barrels are still marked 5.56 though.

Quoted: Lady seems to me that Y O U were the one who did NOT get it.....oh well, sometimes hormones can be tricky :), nevermind like you guys say 'water under the brigde'. (i know she's not gonna  like that comment :)

no, i get it.  i live with him.  i think i know what the hell he's asking, i mean, it's not like we didn't discuss at all.  

yeah, we can find the caliber stamped on the barrel, true.  but we have to have the damn firearm in front of us to be able to check that.  and since we aren't lucky enough to own an AR from every manufacturer, we can't check the barrel, now, can we?  again,

minman, i don't know about that sexy thing.  you'd have to ask the fiance, but my guess is he'd say 'no'.  i think he's afraid more than turned on.  something about me being able to shoot better than him and knowing the combo to the safe.  

I just hate crap like this! I don't understand why they can't get it sorted out and all be the same.

On a related note, when I get ready to reload do I have to buy 5.56 reloading dies, or .223? I can't seem to find 5.56 stuff. All the reloading tools and info I have must be for .223. [:\]

So where do I get info on reloading 5.56? But wait, my Sierra manual indicates reloading for .223 with surplus 5.56 cases. What do we call this little critter?

Maybe I will sell all my guns and get into something more standardized like "experimental heart surgery"

Quoted: I just hate crap like this! I don't understand why they can't get it sorted out and all be the same. On a related note, when I get ready to reload do I have to buy 5.56 reloading dies, or .223? I can't seem to find 5.56 stuff. All the reloading tools and info I have must be for .223. [:\] So where do I get info on reloading 5.56? But wait, my Sierra manual indicates reloading for .223 with surplus 5.56 cases. What do we call this little critter? Maybe I will sell all my guns and get into something more standardized like "experimental heart surgery"

LOL!

and thank you for injecting some much needed (non-sarcastic, non-condescending) humor into this discussion.

Quoted: Quoted: I just hate crap like this! I don't understand why they can't get it sorted out and all be the same. On a related note, when I get ready to reload do I have to buy 5.56 reloading dies, or .223? I can't seem to find 5.56 stuff. All the reloading tools and info I have must be for .223. [:\] So where do I get info on reloading 5.56? But wait, my Sierra manual indicates reloading for .223 with surplus 5.56 cases. What do we call this little critter? Maybe I will sell all my guns and get into something more standardized like "experimental heart surgery" LOL! and thank you for injecting some much needed (non-sarcastic, non-condescending) humor into this discussion.

Agreed!
Can we be friends now?
HUNTER FROM ARGENTINA
OUT.
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I was just looking at some info posted at home.sprynet.com/~frfrog/miscelld.htm#5.56%20mm%20NATO and they state

"It must also be noted that all 5.56 x 45 mm NATO ammunition (such as US M855) requires a 1:9" twist or faster rifling to stabilize the long 62 gr ball bullet and a 1:7" twist to stabilize the extremely long tracer variation.  The standard twist used for .223 Remington commercial chamberings is 1:12" or 1:14" neither of which will stabilize the NATO type ammunition. The NATO ball ammunition is easily identified by its green bullet tip."

Sooooooo, can twist rate give us an indication of chambering? Generally speaking?  

Well th answer to that is no . Twist rate has notheing to do with chamber dimensions .