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View Full Version : Did I get .223 and 5.56 mixed up somehow?


MrDickey
06-19-2012, 12:33 AM
So a member of another forum I'm with posted a...I thought was a fair and honest...question that I attempted to answer. The italicized was the OP. followed by my response, and the underlined was somebodies response to my input. Just wanted to double check...what exactly do I have that's inaccurate? I'd just like to make sure the information I've read and have been told is correct and that I'm not misleading someone new to the game. Any and all input would be great...

Originally Posted by stunter

Help a noob out here what .cal is it??? .223 or 5.56? Sorry if its a stupid question but I don't know anything about ar's other then before long wife and I both want one..we went to the range and shot one and fell in love with it..

I'm looking at your name and it has a 223 into it and could assume its a .223 cal but you know what they say about assuming..lol



Noobs don't ask honest questions, they try to answer them when they don't know jack. ;-)

5.56 and .233 are both essentially the same thing. The only difference is pressure in each round. 5.56 is what NATO uses because it "punches" harder than .223. .223 is what us civies use because we're not running through the streets of Baghdad with the NEED for that power.

That being said, all ARs can run .223. SOME can run 5.56 as an added plus. To make a terrible analogy (Never was good with those) think of it as having a car that takes regular gas and FLEX FUEL. They both do the same thing essentially, one is just a little stronger and pricier than the other.

If I could guess by the love it looks like was put into this one I would GUESS 5.56, but assume .223 and only use .223 unless otherwise confirmed. Again, they're both essentially the same thing. Even look the same.

Not sure if that helped.

Stunter, Leatherknife's reply is a great example of why you should always check and validate information you see on the internet. His facts are not acurate. Since this is a sales thread we shouldn't generate any discussion about this. Your instinct not to assume anything is on target and your question is appropriate. Hopefully heath223 will clarify the specs for the chamber on this rifle. The components heath223 used in this are excellent. It apprear that this AR was built for accuracy and I suspect with a quality optic like the Nikon he is including it's a superb shooter.

04slogoat
06-19-2012, 12:36 AM
:popcorn:

MrDickey
06-19-2012, 1:32 AM
:popcorn:

Not exactly the help I was looking for.

anymoose
06-19-2012, 1:34 AM
looks right to me, wikipedia agrees fwiw

MrPlink
06-19-2012, 1:45 AM
What the hell is the point of this garbled post?

stix213
06-19-2012, 1:59 AM
Using the 'quote' mechanics of the forum helps, cause I'm having trouble telling where one post you're quoting ends and the next begins.

In general though they are close to identical. An AR chambered for 5.56 can fire both, one that is chambered for .223 could become damaged if trying to fire 5.56 because 5.56 is spec'd for a higher max pressure. That's generally a good enough explanation for someone without getting into the nitty gritty details.

S470FM
06-19-2012, 2:27 AM
i'm thoroughly confused. thanks.

scglock
06-19-2012, 3:30 AM
wait... what? I am so lost

PEZHEAD265
06-19-2012, 4:01 AM
Who is on first????

Zartan
06-19-2012, 4:33 AM
http://t0.gstatic.com/images?q=tbn:ANd9GcSXTd3uEMx_ur1fFyMEHWlO07YAMEYMB PqFFOE0kYG325BQdsr4

oh, and italics fail

the86d
06-19-2012, 4:33 AM
5.56mm and .223 caliber are ALMOST identical.

The neck is a bit different, but 5.56 is based on the .223, but what I have found is that it is typically loaded hotter.

If you were to shoot some say M855 in a specifically .223 barrel you could theoretically over pressure the chamber and blow the firearm into pieces (chamber?), or cause hairline cracks that would cause it to blow to pieces in the future... from what I understand.

If you ever get a chance to shoot some basic .223 rounds, then drop some say... M855 in the second half of the magazine, you will notice a definite recoil difference. 5.56mm rounds are typically loaded hotter (to higher pressures) to penetrate helmets at greater distances than .223.

.223 should have no problems in 5.56 chambers, but the pressure of a 5.56 in a .223 chamber COULD be a bad thing. I read that a Wylde chamber is fine for 5.56mm (in a ".223 WYLDE chamber").

Lawmonkey33
06-19-2012, 5:26 AM
Looks good to me too

TNP'R
06-19-2012, 5:35 AM
You lost me at. So a member of another forum I'm with posted a...

sonnyt650
06-19-2012, 5:47 AM
If you take off the rails/handguards you'll typically see a marking that indicates whether a particular barrel is designed to shoot 5.56. If it's marked .223 and is of recent manufacture then don't risk it since 5.56 ammo (62gr steel penetrator for example) will sometimes put the bullet ogive much closer to the rifling than would .223. If seated against the rifling in a .223 barrel, firing will cause higher pressures.

When used in a 5.56 barrel there's an ongoing debate regarding the higher pressures of 5.56 versus .223 where it depends on how it's measured. If you read good reloading recipes the measured pressures that are quoted for .223 are the same as for 5.56 elsewhere, no distinction made at all where I haven't seen any 5.56 recipes and warnings associated with them. For civilian ammo it may be that what 55gr ammo is sold as (5.56 or .223) depends on the headstamp on the cases more than some change in the load.

I'm not sure why Lake City 5.56 brass is typically thicker than .223 but it's not due to the pressure: since brass is a poor pressure vessel compared to the steel chamber it is used just as a "gasket". It reloads great though so I'm not complaining, but it's probably because it needs to expand out to the out-of-spec oversized military chambers without failing.

NiteQwill
06-19-2012, 5:50 AM
There is no internal or external case differences between .223 and 5.56. The volume is the same in both cases.

5.56 is NOT AWLAYS thicker than .223. Not sure? Measure cubic/water volume of the two identical cases made by the same manufacturer (Lapua, for example) and you will get the SAME reading. "Thicker" casing is a popular internet myth that continues to be spread. The differences lay between two different manufacturers, not one in the same. Remember, all manufacturers are different and only accomodate SAAMI and NATO specs to their liking.

Ask any serious reloader or high power shooter about the differences and you will get a "there is none" reply.

The differences between the two cases are not in the cases, actually. They are in the chambers of each respective cartridge. The leade (throat) in 5.56 chambers is longer, thus able to accomodate .223 easily. Conversely, the leade in .223 chambers are short.

Read this, from top to bottom: http://www.6mmbr.com/223rem.html

xpbprox
06-19-2012, 5:56 AM
Niteqwill, so the neck and case thickness are the same?

OP, The guy who responded to your post claiming it was inaccurate was an ***.

DarkSoul
06-19-2012, 6:07 AM
I reload a ton of .223/5.56 and have measured and weighed many different cases, and have found both specs all over the place, none are consistently thicker or heavier than the other.

As for case pressure, Quickload software, (FWIW) states they the maximum cup pressure for Remington .223 is approx. 55000psi, and the SAAMI 5.56 is approx. 62000psi (I say approx. because I am not at my computer looking at the software, this is from memory).

But to answer the OPs question, the guy on the other forum is just trying to flex his e-peen, and has failed IMO, the other guys explanation is pretty decent, but, you should still see what the owner of the rifle says to be safe. Now with all that being said, personally, I would always just build off of a 5.56 barrel to be safe, although I load all my own ammo, I always load with the 55000psi max in mind.

NiteQwill
06-19-2012, 6:18 AM
Niteqwill, so the neck and case thickness are the same?

OP, The guy who responded to your post claiming it was inaccurate was an ***.

No, not necssarily. They will be inherently different among manufacturers and even within.

For example. LC 2008 and newer brass generally has a neck thickness of .010". But take a look at their older brass and you will see that it was thicker back then (80's to 2000's) @ .013-.016". All manufacturers differ.

The differences between the two cartridges are chamber leade and SAAMI and NATO CUPs.

Not many books have reloading data on 5.56... why? Because they are generally loaded to .223 data. Disclaimer: Load at your own risk, check for signs of pressure, and always start well below the maximum limit. ;)

xpbprox
06-19-2012, 6:34 AM
Ahh I see, that's what I was thinking (variances in manufactures) thanks for clearing that up.

the86d
06-19-2012, 6:57 AM
There is no internal or external case differences between .223 and 5.56. The volume is the same in both cases.

5.56 is NOT AWLAYS thicker than .223. Not sure? Measure cubic/water volume of the two identical cases made by the same manufacturer (Lapua, for example) and you will get the SAME reading. "Thicker" casing is a popular internet myth that continues to be spread. The differences lay between two different manufacturers, not one in the same. Remember, all manufacturers are different and only accomodate SAAMI and NATO specs to their liking.

Ask any serious reloader or high power shooter about the differences and you will get a "there is none" reply.

The differences between the two cases are not in the cases, actually. They are in the chambers of each respective cartridge. The leade (throat) in 5.56 chambers is longer, thus able to accomodate .223 easily. Conversely, the leade in .223 chambers are short.

Read this, from top to bottom: http://www.6mmbr.com/223rem.html

Okay cool... I was still reloading the WallyMart Federal as many times as I was Lake City. Good to know. :)

jsipe007
06-19-2012, 7:00 AM
MrDickey, I understand your confusion! you did not comment on the quality of the firearms for sale, but merely suggested that if you don't know the proper chambering of an ar-15 you should stick to .223 cartridges in order to avoid an unsafe situation. While I too feel that it would be unlikely to find an ar-15 chambered just for .223 since most people like the versatility of being able to shoot 5.56 as well, its safest in this circumstance for him to assume its chambered for .223 until he can actually inspect the barrel.

The largest difference between .223 and 5.56 rounds is headspace. The .223 has a shorter headspace and for this reason can easily be fired in a 5.56 chambered rifle. 5.56 in a .223 rifle, however, is not a good idea since 5.56 has a longer headspace and the round has the possibility to rupture upon entering the chamber. Heres a great link for all those still interested on the topic.... :)

http://www.ar15armory.com/forums/556-223-Ammunition-Ch-t22582.html

HK Dave
06-19-2012, 7:03 AM
The point of this thread is as follows...

http://imagemacros.files.wordpress.com/2009/09/butthurt_report_form.jpg

em9sredbeam
06-19-2012, 7:03 AM
I am going to have to copy someone from awhile back and Say
"This thread is brought to you by the letter alcohol."

kendog4570
06-19-2012, 7:14 AM
Where are all the damaged rifles/barrels/chambers from firing this nasty 5.56 in .223?

What is the actual difference in the headspace dimension between the two?

Betcha dont know.

This topic is almost as insidious as the the "Clymer headspace gauges are closer to Mil-Spec for the Garand" drivel on the CMP and surplus rifle forums.

If this keeps up, I am going to be forced to file the form posted above! ;)

17+1
06-19-2012, 9:33 AM
Where are all the damaged rifles/barrels/chambers from firing this nasty 5.56 in .223?

What is the actual difference in the headspace dimension between the two?

Betcha dont know.

This topic is almost as insidious as the the "Clymer headspace gauges are closer to Mil-Spec for the Garand" drivel on the CMP and surplus rifle forums.

If this keeps up, I am going to be forced to file the form posted above! ;)

So, will my primers start flowing around my firing pin if I use 5.56 in my .223? ;) :p

kendog4570
06-19-2012, 9:54 AM
So, will my primers start flowing around my firing pin if I use 5.56 in my .223? ;) :p


You're special. You probably have too many matchheads in with your powder charge.

MrDickey
06-19-2012, 12:49 PM
MrDickey, I understand your confusion! you did not comment on the quality of the firearms for sale, but merely suggested that if you don't know the proper chambering of an ar-15 you should stick to .223 cartridges in order to avoid an unsafe situation. While I too feel that it would be unlikely to find an ar-15 chambered just for .223 since most people like the versatility of being able to shoot 5.56 as well, its safest in this circumstance for him to assume its chambered for .223 until he can actually inspect the barrel.

The largest difference between .223 and 5.56 rounds is headspace. The .223 has a shorter headspace and for this reason can easily be fired in a 5.56 chambered rifle. 5.56 in a .223 rifle, however, is not a good idea since 5.56 has a longer headspace and the round has the possibility to rupture upon entering the chamber. Heres a great link for all those still interested on the topic.... :)

http://www.ar15armory.com/forums/556-223-Ammunition-Ch-t22582.html

THIS is aaaaaaaall I wanted clarified. Thanks for the help from those that actually read and offered input.

kendog4570
06-19-2012, 1:36 PM
THIS is aaaaaaaall I wanted clarified. Thanks for the help from those that actually read and offered input.


Just because its on the net dont make it true. I suggest you read "Small arms and Ammunition, Vol. 2, Office of the Chief of Ordnance", and "Small Arms Ammunition Pamphlet 23-1, Dept. of the Army" for a different view.
It is summarized in most copies of Cartridges of the World by Frank Barnes.


From that:

"Cartridge, 5.56mm, Ball, M193
......
Pressure: 52,000psi max. avg.;avg. pressure plus 3 Std.Dev 58,000 psi max."

I think these guys "wrote the book".

I seriously doubt the newer 5.56 ammo is operating at pressures 2000 psi under proof load pressures.

As far as headspace goes, simply look at the chamber and ammunition drawings. They are the same, both minimum and max.

sharxbyte
06-19-2012, 2:37 PM
Not all AR's can shoot .225 or 5.56. Mine's 7.62x39...

In all honesty though, you have the basics correct, and the other guy needs some shpelz0ring help.

stix213
06-19-2012, 3:51 PM
Where are all the damaged rifles/barrels/chambers from firing this nasty 5.56 in .223?


You're not going to find many for several reasons

1) Almost all AR's today are chambered in 5.56. With .223 chambered AR's generally being of a type where the purchaser knows what they are doing, such as a precision upper trying to get minimum MOA out of it. A shooter who just walks into a gun shop and buys an AR without knowing anything about them is almost certainly going to end up with a 5.56 chambering.

2) Shooting 5.56 in a .223 will only damage the rifle if shooting ammo that is made to maximum pressure.

3) A lot of .223 rifles can probably handle 5.56 pressure even if not advertised.

Still, it is a bit irresponsible to be shooting 5.56 out of a .223 AR on purpose.

neal0124
06-19-2012, 4:35 PM
Wow. I didn't even read all the other posts so I don't know if anyone actually really answered the original question from the OP on the other site. The true caliber of both the .223 and 5.56 projectile is .224". The 5.56 and .223 rounds are the same physical size and shape. The 5.56 has crimped primers, sealant on the case mouth and primer and is loaded to higher chamber pressures. The only place that any dimension changes is in the barrel/chamber itself. The 5.56 chamber has a longer free-bore, a smooth bore before the rifling starts, so that it can handle the higher chamber pressures.

Headspace has nothing to do with the rounds. Both rounds can be chambered in either barrel. Get a case gauge and drop a .223 in it, then put a 5.56 in it. They will both fit fine.

kendog4570
06-19-2012, 4:59 PM
Still, it is a bit irresponsible to be shooting 5.56 out of a .223 AR on purpose.

Not buyin' it.
Look at the drawings, and look at what the original design pressures were(are).
The throat datum for the .223 SAAMI chamber is .222" X 1.830"
I have never seen a drawing for 5.56 ammo, but any rounds that I have measured have a max throat datum of the same, or less. The majority by far were significantly shorter. So, even if the bullet ogive is kissing the lands on a new chamber, it wont be in 200 or 300 rounds. Just touching the lands will not cause the damage that is warned about constantly on the net. It is very common for highpower shooters to jamb the bullet .015" or so into the lands for optimum accuracy. No pressure problems there, at least not to cause damage to the rifle. Maybe brass life is a little less. A tight neck will definitely cause pressure spikes, but the 5.56 chamber neck is larger, so no danger there.

With all the 5.56 ammo that has been sold on the US market ever since Poon Sang first brought PMC to the market in the late 70's, there should be a metric ton or two of scrap .223 sporting rifles, with "damaged chambers" from shooting this stuff.
Have you seen any?

You haven't because it doesn't happen.

weber_2
06-19-2012, 7:13 PM
The AK is a far superior weapon then the AR.

jsipe007
06-20-2012, 6:55 AM
If there is no difference in headspacing, why do .223 headspacing gauges not work with 5.56? 5.56 headspacing gauges work with both .223 and 5.56.

http://www.ar15.com/forums/t_3_4/535124_.html&page=1

Damaged .223 chambers, in my opinion, dont exist because the .223 and 5.56 are very similar rounds. When a 5.56 cartridge is fired in a .223 barrel, the pressure is around 20,000 psi higher than when a 5.56 round is fired in a 5.56 chamber. The slight difference in headspacing is one of the causes for this psi change. typical pressures of a 5.56 round are at 52,000 to 58,000 psi. Increase that by 20,000 and you have a range of 72,000 to 78,000 psi. The army tested the 5.56 case up to at least 70,000 psi, and the standard .223 barrel can withstand pressures up to around 76,000 psi. While not in the "optimal" range, the cases and barrel were able to withstand the pressure, and for this reason there are very few "blown up" .223 rifles due to 5.56 rounds. I, personally, feel that firing 5.56 from a .223 barrel is a bad idea just because it was not meant for that cartridge. Most people would agree that 5.56NATO is charged higher than .223 and although the numbers may show that it is safe, just the other day I had a "squib" load from a brand new box of Federal .45ACP. This one squib load showed me that even new ammo isn't foolproof. If one were to get a 5.56 round with a little added charge, i would much rather be firing that round from a 5.56 barrel because it gives me the greatest margin of error.

this is a great resource for those interested... unfortunately its not the full book, but it still has great info.

http://books.google.com/books?id=3_-kUkNXTNwC&pg=PA497&lpg=PA497&dq=Small+arms+and+Ammunition,+Vol.+2,+Office+of+th e+Chief+of+Ordnance&source=bl&ots=Y4KF-kJnmA&sig=hZiWJPtfa_uovsnBmQjhujCI1m0&hl=en&sa=X&ei=gfvgT4WZHKno2gWAi43LCw&ved=0CFMQ6AEwAg#v=onepage&q&f=false

xpbprox
06-20-2012, 7:12 AM
The AK is a far superior weapon then the AR.

:43: