5.56 versus 223 ????

[GRUMPA]

This may sound like a dumb question but I'm going to ask it anyway. Kinda makes it easier to since I don't have to look at the expression on peoples faces when they read this.:lol:

I have heard all of a sudden reference to the 5.56 cartridge and have done some (not a lot) searching into it. I'm kinda old school still and all my books are for the most part old. When I take any of them down and thumb thru to the 5.56 section it's labeled as 5.56x45.

OK now that same thing is listed in for the 223's :confused: there aren't 2 different cartridges but rather just the one. I own 2 rifles in 223 and use the same loads in both without so much as an issue. Velocities thru the chrony are at 3100FPS on both and work flawlessly.

My Mini-14 has it stamped on the receiver 223 cal. and as far as the Colt AR-15 that's in storage and I don't intend to unbury the thing at the moment to find out.

From what I've found out so far, the 2 by outward appearances are alike. It seems that pressure is what's an issue and so far that others have reference to the "LEADE" in the chamber itself.

When reloading for both of my rifles in the past I've always found out what the free bore was and in both cases the round would not even work in the magazines because they would be about .025 to long. So in incense they are only about .015-.020 longer than factory specs.

All of my brass is over 15yrs old and in all honesty neither rifle has ever had a factory round in it, but all the cases I have either have 223 (factory stuff) or 5.56 with the NATO cross on it, but I never have loaded anything hotter than 3100FPS as I don't really see a need to.

Am I getting my wires crossed or is the difference primarily in the pressures created between the 2?

And since they mention that the 5.56 has a longer leade in the chamber is that to accommodate the higher pressure round?

I may not have explained it well but I'm doing the best I can here.

[felix]

There might even be more variation between any manufactured ammo in any caliber. I can say the same about the guns I have here, especially revolters. Military rifles throughout the world? Many, many variances in chamberings with respect to their nameplates. ... felix

[GabbyM]

You’ve got most of it.
Chamber reamers are different. They are different chambers not rounds. Compromise is the match chamber by Billy Wylde. You’ll see that in many HP Rifle competition barrels.
NATO chamber is also larger in diameter and head space which is why the brass looks so blown out. When you look at the case heads of once fired 5.56mm NATO brass it’s easy to see what the over 60,000 psi does to them. Of course the Army doesn’t care much how bad they beat up the brass.

Last AR I built was a bull barrel with 223 REM chamber. Since I’ve no plan to wade rivers with it or take it into the sand box. If you adjust your 223 REM fl size die to just barely bump the shoulder you’ll not oversize them too much for a NATO chamber. If you run a case fired in a NATO chamber with a 223 die all the way on the shell holder you’ll stretch the case quite a bit. When you size once fired surplus brass you pretty much have to run your size die all the way down to get the bases sized and make sure every case will chamber. I always end up with a lot to trim off. However I think I’ve a lifetime supply now. Good deals right now on new LC brass which looks to me a lot better rout than the beat up fired Mill brass.

You can find chamber drawings on 5.56mm NATO and 223 REM to compare.

[GRUMPA]

I'll have to go look up the chamber drawings when I get back form cutting firewood. But from what I knew (or didn't know) that when AR's were built for civilian use, they had 3 different chamber gauges. They were No Go, GO, And Field, with Field being the largest of the 3.

[tomme boy]

Gabby, The 5.56 rounds are loaded hotter. They are not loaded the same. Some also say that the brass is longer on the 5.56. As others have said, the freebore is longer on the 5.56. This allows the preasure to not spike as fast. Works the same as the Weatherby chamberings.

[Larry Gibson]

tomme boy

I wouldn't bet the farm that the 5.56 is loaded "hotter". That is a myth the same as it is with 7.62 NATO vs .308W. Some is and some isn't, just depends on the lot and manufacure of each. I've pressure measured lots of both BTW.

Grumpa

It is a matter of chamber specs, particularly the leade as mentioned. The use of M193 (the 55 gr FMJBT laod) in either chamber (5.56 or .223) doesn't seem to pose any problems. However, the use of M855 (62 gr FMJ "green tip") in the shorter throated .223 chambers can cause pressure problems with some lots of that ammuntion. Your Mini14 and AR (unless either have a match or custom barrel...then a chamber cast is in order to see what the leade is) are compatable with the commercial loadings of up to 55 gr bullets and milsurp M193. If both have the faster 7" twist (ruger) or a 7 or 9" twist in the AR the chambers should be compatable with both types of ammo.

If the AR15 is an older one with the 12" twist (best for cast bullets:-) BTW ) then it is compatable with commercial ammo of 55 gr bullets or less or the milsurp M193 with 55 gr FMJs. Back "in the day", before all this hype the chambers of all ARs and Mini14s were cut to milsurp specs for M193 ammuntion. My M700V also had a milsurp spec chamber (bought in '72) even though marked .223. However, my M70 XTR (bought in '85) has the tighter SAAMI spec .223 chamber. Both of those have 12" twists and shoot just fine with M193 ammo.

Larry Gibson

[xfoxofshogo]

i have a AR15 in the 5.56 and a 223 rifle at my house right now and i shoot the AR15 5.56 chamber and shoot 223 and 5.56 in it now
i mic the brass unfired thay come out the same
what i see that not the same is 223 dose not have crimp primers i look at some i shot and thay come out a bit off

i think some are right in the chambers are made a bit on the big side for the 5.56 and thay mabe like a hot 223 and the primers are a bit beter in the 5.56 to keep it form slam fireing
and how knows mabe its just to cover ther *** in case some thing gose boom thay can clame it was the rong ammo in the rone gun who know

o and it might be thay do not whant you to put a steel 5.56 in a 223 a lot of the ammo out ther for AR15 is steel not brass and the steel haves a coting on it some times builds up in the chambers

[tomme boy]

If it is " TRUE " 5.56, it is loaded hotter. Some of the stuff that is marketed today as 5.56 is not as fast as the true stuff.

[tomme boy]

The coating on the steel cases has nothing to do with the case not extracting. The real cause is the steel itself. It is not as elastic as brass. When it expands, it sealls itself to the chamber. Same as brass. Now here is the differance. The brass springs back and releases from the chamber when the preasure goes down. The steel does not spring back as well. So it is stuck in the chamber. The Russian guns get around this by having an extractor 2x as big as a AR has. It grips more of the rim so it can rip the case out of the chamber. The Russian guns are not the best out there, but they build them to work no matter what.

[GRUMPA]

OK this is the second attempt to do this as my internet seems to have the hic-ups and I'm getting short tempered.

I had this nice looong response only to have it go ka-poot.

Anyway I got back from doing chores and was going thru the net and stumbled across this page that has different chamber dimensions:
http://ar15barrels.com/data/223-556.pdf
So far I have not noticed any dimensional differences in the cartridge itself only in the chamber.

And Gabby that is actually what I do when I reload for that particular rifle (second firing). I figure it's fire formed to the chamber and that's what I'm after.

Larry the AR is a 1-7 twist and the brass is noticeably larger after firing and the Mini is a 1-9 twist but both have only used 55gr FMJBT. I have not yet used anything larger (as far as weight) in them just yet. Even though a person reloads I still after every firing count the cost of what that trigger pull cost me. When I'm out in the field the brass from the Mini might be going to the next county, it's dang hard to find it unless I'm bench resting it.

And XOXOXO (whatever) there's 2 things that I never do. Use steel cased anything and win the lottery.

I'm hoping for some military/reloader type of a person to chime in on this. From outward appearances it's the chamber that defines 5.56/and or 223.

[Larry Gibson]

Well, I'm retired military with 42 years in. Also have been reloading for the .223 and the 5.56 since '69 so I'll chime in again; "From outward appearances it's the chamber that defines 5.56/and or 223". That is correct.

Larry Gibson

[tomme boy]

http://en.wikipedia.org/wiki/5.56%C3%9745mm_NATO

Read this.

http://en.wikipedia.org/wiki/.223_Remington

Then this.

http://ammo.ar15.com/

This one is a really good one

[GRUMPA]

Thanks Larry, it just makes me better understand things on a pin-point level. I appreciate your input and now that dim light I have finally got a bit brighter.

And thanks tomme boy I got it bookmarked for later reading.

[MtGun44]

Larry's post #6 has the keys.

Bill

[DukeInFlorida]

You'll be resizing with .223 Rem resizing dies.
So, reload any brass with confidence.

Unless you are expecting to win competition shoots, don't worry about mixing headstamps.

All (well, just about all) of my AR ammo gets blasted at 720 rounds per minute, and I've never had a failure to load or fire.

If you're going to shooting prairie dogs at 600 yards with a bolt action, sort by headstamp. You'll still be reloading with .223 Rem dies, so no worries.

[GREENCOUNTYPETE]

RUGER says the Mini will accept 5.56 with out a problem in the 1978-2004 manufacture rifles i didn't read the manual for the new ones

The RUGER® MINI-14® RIFLES are chambered for the .223 Remington
(5.56mm) cartridge. The Mini-14 Rifle is designed to use either standardized U.S.
military, or factory loaded sporting .223 (5.56mm) cartridges manufactured in
accordance with U.S. industry practice.

[Larry Gibson]

DukeInMaine makes a good point; try buying a set of 5.56 loading dies....or 7.62 NATO loading dies for that matter.......

Larry Gibson

[KCSO]

Waters tested the 223 vrs 5.56 a long time ago and found little difference in his rifles. AFAIK the biggest difference was the more generous chambers in some military rifle and now the hevier bullets in a lot of the military stuff. My friend uses a LOT of LC brass for his varmit loads and says that the oly difference is 1 grain of case capacity. His Varmit loads are shooting under 1/4" at 100 yards so until I can beat that I just keep quiet.

[JIMinPHX]

I looked into this several years ago. It used to be a hot topic on some other boards, especially ones that lean more towards military rifles. After much reading of books, internet posts & gun owners manuals, my interpretation was this -

There is a slight difference in the specified throat dimensions between the two designations. Some reloading manuals give separate loading data for the two designations, others treat them as one in the same. The actual military specification for M193, M855, etc. can be found in the back of Cartridges Of The World. The actual specifications of the .223 can be found on the SAAMI website. The big difference that I remember was that the SAAMI spec listed a max pressure, where the military spec listed a minimum velocity. I don't have access to my books right now, so I can't look up all the details. This is all just off the top of my head.

I read that the new H&R handi rifles come with a warning not to shoot 5.56mm ammo, but only .223 ammo. My H&R is older. It didn't come with that warning. It saw a steady diet of M193 for years. I had no signs of trouble.

[pilot]

No way would manufacturers make two different cartridges with power levels different enough to cause a problem if you interchange them. The liability insurance for that would kill them. They would do something like the difference between the 38 Special and 357 Magnum. There is a .10 inch difference in case length in those so you can't chamber a 357 in a 38 Special chamber.

[JIMinPHX]

Some specification highlights:

M193
3250fps +/- 40
52,000psi Max ave.
58,000 psi Max +3 Std Dev
Port Pressure 15,000psi 2,000psi
2" mean radius @ 200yds
Source: Cartridges of The World #9 page 476

.223 rem
55 grain 3215fps
52,000 cup max ave
53,300 cup max probable lot mean
Source:http://www.saami.org/specifications_and_information/publications/download/206.pdf actually page 20, but labeled "page 14"

According to the Speer #13 reloading manual page 137 -
The 223 Rem resulted from military development of a new service cartridge. Adopted in Feb, 1964 as the 5.56mm Ball Cartridge M193, it was introduced as a commercial cartridge by Remington one month earlier.

I seem to remember that some other manuals list the two cartridge designations as separate entities, but I don't have those books in front of me right now.

[Larry Gibson]

JIMinPHX

Let's not confuse "internet" facts with actual facts, you could really confuse some[smilie=l:

Larry Gibson

[JIMinPHX]

Larry, are you saying that I am posting "internet facts"??

I consider the SAAMI website to be a fairly good reference. The PSI spec in their PDF matches the data in my loading manuals. Am I missing something?

[Larry Gibson]

Larry, are you saying that I am posting "internet facts"??

I consider the SAAMI website to be a fairly good reference. The PSI spec in their PDF matches the data in my loading manuals. Am I missing something?

Not at all....I was implying your posting of the facts could indeed confuse the "internet facts" (opinions).......you are correct and BTW; I also use SAAMI as a reference:drinks:

Larry Gibson

[WineMan]

Of course there is the 38 ACP and the 38 Super. Same brass, same chambers (I am not counting the newer headspace on the shoulder ones) but different pressures. Best not to fire the 38 Super in the older Colt 38 ACP. I do not think there are any commercial loads for the 38 ACP but there is still a small liability.

Wineman

[WilNsc]

My understanding is the rounds are the same, but the 5.56 chamber is 'looser' for reliable feeding/extraction on full-auto and sustained single shot fire. Brass condition dosen't matter to the goverment it's more about reliability.

I've never tested it, but I can imagine if you had 2 M-16's side by side and on full auto, the .223 chamber would start to jam sooner when heated after a few hundred rounds of sustained fire.

[MGySgt]

Jim - Someone is going to look at your figures and state the chamber pressure is the same - They are not!

One is in PSI and one is in CUP. The last I knew they were not interchangeable.

[Hamish]

Nobody get they shorts inna wad. This discussion is EXACTLY why we need these discussions.

Case in point: Wikipedia. We have'nt the slightest idea who posted ANY of it's content, and for how many seconds in a row that it's content will remain the same.

(I wish this thread had come around before I tried to shoot a round of steel case out of a .223 Contender barrel.)

[45-70bpcr]

No way would manufacturers make two different cartridges with power levels different enough to cause a problem if you interchange them. The liability insurance for that would kill them. They would do something like the difference between the 38 Special and 357 Magnum. There is a .10 inch difference in case length in those so you can't chamber a 357 in a 38 Special chamber.

Not always. A .375 Win will unfortunately chamber in an old lever gun made for 38-55.

[KCSO]

First I will refer everyone to Ken Waters test of the 223 in 1980 and his results with 5.56 Vrs 223.

Now as to the varnish coating on the steel Wolf cases. In hot weather or in a hot chamber the coating does come off and coat the chamber. I have cleaned a LOT of gunked up chambers from shooting this stuff. I have sample cleaning brushes in the shop showing the gunk you get out if you don't clean well after using Wolf ammo. There is nothing wrong with shooting this stuff, IF you clean the chamber afterwords and if you don't care about pin point accuracy.

I have personally fired and measured base dimensions on every 556 and 223 ammo I could get ahold of. I find NO ammo loaded any hotter than factory standard ammo using Federal FMJ as a base line. I have found no ammo with significantly larger dimension than factory standard. LC 80 ammo is only 6 thousnads longer than factory new Federal and that is about as much variation as there is between Winchester and Federal.

[KCSO]

First I will refer everyone to Ken Waters test of the 223 in 1980 and his results with 5.56 Vrs 223.

Now as to the varnish coating on the steel Wolf cases. In hot weather or in a hot chamber the coating does come off and coat the chamber. I have cleaned a LOT of gunked up chambers from shooting this stuff. I have sample cleaning brushes in the shop showing the gunk you get out if you don't clean well after using Wolf ammo. There is nothing wrong with shooting this stuff, IF you clean the chamber afterwords and if you don't care about pin point accuracy.

I have personally fired and measured base dimensions on every 556 and 223 ammo I could get ahold of. I find NO ammo loaded any hotter than factory standard ammo using Federal FMJ as a base line. I have found no ammo with significantly larger dimension than factory standard. LC 80 ammo is only 6 thousnads longer than factory new Federal and that is about as much variation as there is between Winchester and Federal.

[Larry Gibson]

Jim - Someone is going to look at your figures and state the chamber pressure is the same - They are not!

One is in PSI and one is in CUP. The last I knew they were not interchangeable.

You are correct in that there is not any real correlation between C.U.P. and piezo transducer/strain guage psi's. However up untin the last 10-15 years or so many C.U.P. pressures were listed as "psi". That is the case with Jim's quoted pressures; they are all really C.U.P. pressures even though the first are listed as "psi".

SAAMI transducer MAP for the 223 Rem is 55,000 psi with the MPSM being 58,500 psi. SAAMI does not list the military calibers. The 5.56 is currently measured at the case mouth with transducers at our arsenals. I'm not sure what LC is using as it is civilian owned now. I can tell you however, having measured the psi with a M43 PBL I have found the psi of various lots US M193 and M855 to be above and below that of the SAAMI MAP/MPSM for the .223. I've also found some factory .223 to run above the MAP but all of it has been below the MPSM as it should be.

Larry Gibson