.223 vs. 5.56

[Bloodman14]

O.K., gents and ladies, I am entering new territory on this one and need some advice from the more experienced among you. Will start reloading for a friend's M-4 style carbine; his components and tooling, my press and time. My Google-fu is pretty strong, but need clarification from those I trust.

1. The .223 Rem. and the 5.56 x 45 NATO are physically the same case, correct?
2. If so, can I use 5.56 data for both cases? Arm in question is a PSA marked 5.56 with a 1:7 twist. Bullet weight recommendations?
3. I understand that the chamber dimensions are what's different, correct? (One can fire a .223 in a 5.56 chamber, but not vice versa due to chamber pressures.)
4. Plan on using H335, have an 8-pounder. Will start in the mid-range of the data.

Any other assistance would be appreciated. Thanks.:coffee:

[Winger Ed.]

A lot of .223s have a 10 and some even a 12" twist.
They don't like bullets over 53-55gr.
The military started off with 55gr. and a 10" twist then went down to 7" over time to handle the heavier bullets.
On the other hand-
Some bullets like Hornady's SX series do well with the 12" but can and will fly apart coming out of a 1-7 twist barrel.

They don't even mention it anymore, but older manuals said to drop your powder charge 1 grain to compensate for the thicker walls
of GI brass and equal the data in their .223 and 5.56 section.

[BLAHUT]

These are two different animals from the same mother. .223 is civilian, 5.56 is military and higher pressure. military has smaller cast compacity, thicker case. Some loading charts say to drop your powder charge in the military case. A 1/7 twist you should be able to shoot 80gr bullets and stabilize them, just won't unless you single load, too long for clip length. If you just stuff heaver bullets in the case you will rase pressures and safety issues. As with any gun just start low and work up and find the accuracy load.

[racepres]

I don't buy into some of the "heavier brass" verbage... weigh some... may surprise you!!!

[M-Tecs]

Lots of misinformation floating around on this subject even from so called reliable sources. Unless the claims are based on actual pressure tests and case volumes they are just repeating myths and misinformation.

The original M16 601 was a 14 twist. Winter testing showed stability issues with the 55 grain M193 ball so the twist was changed to 12. When the switch was made to the SS109 NATO 62 grain steel core the twist was changed to 7 twist. http://bpullignwolnet.dotster.com/retroblackrifle/

The 5.56 military verse civilian .223 case volume is a non-issue unlike the 308 & 30/06. Within manufacturers specs case volumes are the same with LC tending to have the most volume. Externally the cases are the same. Actual weights and volumes in the center of the article https://www.accurateshooter.com/cartridge-guides/223rem/

https://forum.accurateshooter.com/threads/my-updated-223-5-56-h20-capacity-chart.3998165/

When Remingtin introduced the .223 it had a short throater so the claim was ball ammo would jam into the lands and raise pressure. At one time that may have been true, however, today (most if not all) manufactures chamber their 223's with throats long enough so GI Ball will not jam into the lands.

If it has a 5.56 chamber or a .223 Wylde you are good to go. Same for 99% of the .223 chambers but it's easy enough to check throat length to be 100%.

Larry covers pressures in post #3
https://castboolits.gunloads.com/showthread.php?441484-223-vs-5-56

Other actual pressure test with the same results
https://www.luckygunner.com/labs/5-56-vs-223/

[Hick]

Everyone above pretty much answered your questions-- but to summarize the important part: The most important difference between 223 Rem and 5.56 Nato is that 5.56 is loaded to higher pressures. A rifle receiver built for 223 Rem pressures should not be loaded with 5.56 ammo, but a rifle receiver built for 5.56 can handle 223 Rem. Brass differences are not consistent over all manufacturers. Its the load that matters.

[M-Tecs]

Everyone above pretty much answered your questions-- but to summarize the important part: The most important difference between 223 Rem and 5.56 Nato is that 5.56 is loaded to higher pressures. A rifle receiver built for 223 Rem pressures should not be loaded with 5.56 ammo, but a rifle receiver built for 5.56 can handle 223 Rem. Brass differences are not consistent over all manufacturers. Its the load that matters.

It doesn't work that way. Modern centerfire fire receivers are built to the same specs. Once the bolt and barrel are selected they are installed on the appropriate action size. The action used for .378" bolt face 222 Remington at 50,000 PSI is the same action used for a .473" bolt face at 65,000 PSI.

Cases and primers have very defined pressure limits. Actions are mostly designed around bolt thrust. Pressure is one part of the equation.

GI ball and ball equivalent MX193 & MX855 is the most commonly sold .223/5.56 ammo in the US. Federal was selling it straight from the Lake City Arsenal and Winchester is doing the same. While it is marked as 5.56 there are no warnings about firing in a .223 chamber?????????? Seems like the manufactures and the lawyers at Winchester and Federal are not worried about this issue. Same for all the other ammo manufacturers.

[farmbif]

bullets? are you thinking your going to cast for this? I for one dont, I have bought bulk 55 grain soft points and 62 to 65 grain soft points, I only load hunting or varmint bullets mid south makes their own and they are usually very cheap I also have loaded lots of blemished bullets and seconds from midway they are usually hornady bullets, and for my purposes they are just as accurate as name brand high priced bullets.
ive loaded using 335. start at about 21 grains for 55 grain and 20 grains for the 62-65 grain bullets using cci 41 primers

[downzero]

The difference is irrelevant for your use. Load 25 grains with a 55 and rock on, subtract a grain for 69s and another grain for 75/77 grain bullets. With ball powder you're not winning any accuracy awards anyway, so no sense in over thinking this. Use magnum primers.

[M-Tecs]

With ball powder you're not winning any accuracy awards anyway, so no sense in over thinking this.

BL-C(2) and H322 ball powder was the mainstay of 222 Remington Benchrest shooters for a long time.

This ball powder group doesn't leave much room for improvement.

http://ssaacoffsharbour.org.au/?p=618

https://www.handloadermagazine.com/handloading-the-222-remington

H335 and H322 are still popular with the 100-300 yard Benchrest shooters.

While not at the same level I am getting 3/8" to 1/2" MOA for 5 shot groups out to 300 yards with H335, CFE 223 and AA 2200 ball powders and standard primers with brass that is not close to benchrest prepped. Occasionally I will get a 1/4" MOA five shot groups but I can't do it on demand. That is with my match/varmint rifles mostly with Krieger barrels.

[Hick]

It doesn't work that way. Modern centerfire fire receivers are built to the same specs. Once the bolt and barrel are selected they are installed on the appropriate action size. The action used for .378" bolt face 222 Remington at 50,000 PSI is the same action used for a .473" bolt face at 65,000 PSI.

Cases and primers have very defined pressure limits. Actions are mostly designed around bolt thrust. Pressure is one part of the equation.

GI ball and ball equivalent MX193 & MX855 is the most commonly sold .223/5.56 ammo in the US. Federal was selling it straight from the Lake City Arsenal and Winchester is doing the same. While it is marked as 5.56 there are no warnings about firing in a .223 chamber?????????? Seems like the manufactures and the lawyers at Winchester and Federal are not worried about this issue. Same for all the other ammo manufacturers.

I don't really disagree. Certainly its true that most manufacturers now are making the rifles for either ammo, and the European (CIP) specs do not differentiate, but it has not always been that way. I just don't we can speak for all firearm manufacturers. The pressures are significantly higher with 5.56 and its up to the firearm owner to check to see whether or not the firearm is suitable for 5.56. If your rifle is labeled 223 Rem you need to find out if it can handle 5.56, but If its labeled 5.56 you don't need to sorry about 223 Rem ammo-- that is my point.

[Milky Duck]

Ive used recent manufacture 5.56 in a sporting .223 with no issues..... it might have been a problem once upon a time,but hasnt been mentioned for decades...as for ball powder not being accurate...in the words of Mcenroe.."you cannot be serious"

I can feed my .223 pretty much anything and get combined group hovering around the inch mark.... my go to load is a 50-55grn projectile wit ha 24.5grn charge of AR2206h under it.

[Texas Gun]

223 and 5.56 are not the same they are close the LC 5.56 brass is thicker and i know it is for i have cut them open and
i watch my powder loads close and in a 5.56 it will look like i put to much in it compared to 223

as far as shooting 223 in a 5.56 i do that all the time but 5.56 in a 223 i would be careful about that some one would need to chamber cast them and check
I been told that 5.56 chambers not the same .
now With that i would think 223 ARs would have the same chambers as AR 5.56 m16/m4 5.56
and it would just be the old hunting rifles would be the ones not to shoot 5.56 in

[M-Tecs]

223 and 5.56 are not the same they are close the LC 5.56 brass is thicker and i know it is for i have cut them open and
i watch my powder loads close and in a 5.56 it will look like i put to much in it compared to 223

as far as shooting 223 in a 5.56 i do that all the time but 5.56 in a 223 i would be careful about that some one would need to chamber cast them and check
I been told that 5.56 chambers not the same .
now With that i would think 223 ARs would have the same chambers as AR 5.56 m16/m4 5.56
and it would just be the old hunting rifles would be the ones not to shoot 5.56 in

I've never cut one in half but I have compared volume on a large number of different headstamps and years. I have a large quantity of LC brass starting from the 70's thru 2014. The LC is always at the top or close to the top of having the greatest volume. Some of the foreign GI is near the bottom but it's still within the range of the civilian headstamps.

SAAMI chamber specs on page 68 here https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf

Various chamber spec here https://www.luckygunner.com/labs/5-56-vs-223/#_223_chambers_5_56mm_chambers_everything_in_betwe en_and_beyond

https://ultimatereloader.com/2018/08/05/223-vs-5-56-facts-and-myths/

I also have a supply of actual GI M193 and M855. It's been fired a large variety of 223's chambers without any issues. Nor have I heard of anyone that has had any documented issues despite the various lawyer warnings.

[stubshaft]

In answer to your original question, with a 1 in 7" twist I would start with 69gr. bullets and work my way up. One of my AR's shoot the 69 - 72 grain bullets and the other match grade one likes the 80 grain bullets. The 52-55 grain bullets have never shot well out of either barrel.

[sigep1764]

I have a few PSA rifles in the 1/7 twist. They have preferred the 70 to 75 grain Boolits. The MP 75 grain NATO boolit shoots great with 20 grains of W748. I load it as long as the mags will allow.

[farmbif]

on issue of ball powder and accuracy there is a reason directly related to accuracy why 2520 is call "the camp Perry powder"

[Bloodman14]

Thanks, guys. More info; these will be loaded with j's in the 55 grn. area. The purpose is plinking/practice ammo. I will advise the owner that 70 grn. j's are better suited to this twist rate. I have learned that this rifle has never been fired. Any ideas on break-in procedures?

[Bloodman14]

Hodgdon's site lists a single load using 23 to 25.4 grains of H335. Indicating IMR powders for 70-75 grain j's. Any other load suggestions? I have mostly Hodgdon and Alliant powders.

Oops, made an error, stand by. Still learning on this one, be patient.

[Bloodman14]

Got it figured out, was using pistol data, not the 'rifle' category. Much better. More research before I go any further!

[Texas by God]

There have been no weak action .223 Remington rifles ever made, so I don't- and haven't ever worried about it. I'm loading for two 7" twist and one 9" twist 5.56 ARs.
We shot a ton of 5.56 ammo of all nationalities through my brother's 700VS .223 in the 70s and 80s without even a flattened primer.

Sent from my SM-A716U using Tapatalk

[elmacgyver0]

I have an original Colt SP1 marked .223 that I haven't fired since I bought it.
That is back when I was about 20 years old, I am almost 72 now.
That rifle has less than 50 rounds thru it.
This is an example of an AR that you would NOT want to fire .556 ammo in.

[Tripplebeards]

The only thing I’ve read as mentioned above is 5.56 brass has thicker walls and a longer neck. Just don’t start out with a max suggested book load using military brass. I run all my brand new LC virgin brass through a RCBS 223 FL sizer die and trim all the cases before I start load testing them. So it’s a hybrid case? Lol. Never had any issues running both cases in my 223 LTR and 5.56 POF. The 5.56 factory rounds i believe have a longer OAL (besides longer case necks) could have have problems chambering in some 223’s. I shoot 5.56 rounds in my H&R heavy barrel 223 and have zero issues.

[elmacgyver0]

How about that! I must be getting senile, I just noticed I put the decimal point in the wrong place!
Well, at least I'm not President.

[Larry Gibson]

Thanks, guys. More info; these will be loaded with j's in the 55 grn. area. The purpose is plinking/practice ammo. I will advise the owner that 70 grn. j's are better suited to this twist rate. I have learned that this rifle has never been fired. Any ideas on break-in procedures?

M193 55 gr FMJ bullets, or commercial equivalent such as Hornady's, will work fine for plinking/practice in your friends 7" twist rifle and in the 9" twist also. No need to spend more for "better" bullets just to plink/practice. I shoot thousands of 55 gr fmj's in my own ARs, 7, 9 and 12" twists. The better quality fmj's (the Hornady's) will give excellent accuracy.

H335 has been my standard "go to" powder for loading 52 - 55 gr bullets in the 223/5.56 cartridge since '72. I got my M700V in '72 which was marked 223 Remington. There was none of this internet BS/myth about some difference between the cartridges back then. I had a chronograph in '74 and loaded 55 gr Hornady SXs to the same 3200 fps velocity that the M193 ammo gave out of the rifle which coincided with data from the manuals back then. I used 26.5 gr of H335 under M193 bullets, Hornady 55 gr SXs and Speer 52 gr HPs. I shot lot's of 5.56 M193 out of that rifle, lot's of that H335 load until I shot the throat out. I had the barrel set back 2" and rechambered with a standard Clymer 223 Rem finish reamer (I own it) and shot several thousand more rounds. Finally shot that barrel out completely on a PD shoot a few years back. It's now been rebuilt with a new barrel and still going strong. I've also a M70 12" twist which is a "223 Rem" on its barrel and it digests that load w/o any problems whatsoever. I've also shot out a Savage Competition 223 Rem barrel (9" twist) having shot a couple thousand M855 "Green Tip" rounds through it. That M855 runs 62,000 psi+.

I've had several early Mini-14s, ARs and other gas guns chambered in "223 rem" (as marked on the barrels and/or lower receiver) and they all shoot 5.56 just fine along with my H335 load. In the 10 and 12" twist barrels the 52 gr Speer HP was the bullet of choice for varmints. Many a coyote fell to those. If you're going to load any for hunting/varmints I suggest the Sierra 55 gr Blitz King bullet [not to be confused with the 50 gr Blitz bullet]. Load it over 26.0 gr H335 for an excellent AR load. It has a longer bearing surface and is a long bullet that needs the 7 - 9" twist to stabilize. Should be running 3000 to 3100 fps depending on barrel length. PSI runs right at 60,000.

For last 10 + years the current load manuals have dumbed down the 223 load data back to the SAAMI specified MAP of 55,000 psi. That is why you see max loads of H335 under the 55 gr bullet of 24.5 - 25.5 gr. Using my load of 26.5 gr under a 55 gr J bullet simply bumps it up to original M193 pressure levels and more importantly, velocity levels. I have pressure tested that load [military 5.56 or commercial 223 case, WSR or CCI 450 primer, 26.5 gr H335 with a 52 - 55 gr jacketed bullet] and it consistently runs 59 - 60,000 psi depending on the bullet used. Accuracy has always been excellent.

For long case life and no trimming needed I suggest the use of the standard RCBS 223 Rem X-die in regular commercial, milspec or Wilde chambers. The SB or AR X-die is not needed unless your rifle has a very tight match chamber.

Also, if you try HPs or SPs steer clear of the thin jacketed "explosive" bullets as the jackets won't hold up to the RPM generated by 3100 +/- fps in 7 - 9" twist barrels.

[Bloodman14]

Mr. Gibson, I was hoping you would chime in, thanks so much! I do believe I have enough info to start load development after I decap and FL size this brass. One question remains unanswered; can I use the cases interchangeably with the same load data? Or did I miss that answer?:target_smiley:

[Milky Duck]

you can but your accuracy wont be quite as good as sorted brass...I personally dont bother as my rifle isnt fussy zastava mini mauser.... it will poke pretty much any 50-55grn load into same inch group,always has and hopefully always will.

[M-Tecs]

I have an original Colt SP1 marked .223 that I haven't fired since I bought it.
That is back when I was about 20 years old, I am almost 72 now.
That rifle has less than 50 rounds thru it.
This is an example of an AR that you would NOT want to fire .556 ammo in.

The Colt SP1 was made for the civilian market for 20 plus years. The .223 designation is on the lower receiver.

The barrels and chambers are the same as used on the military 5.56.

The early SP1's did not have a chromed barrel or chamber.

Barrel markings will be one of the following depending on if a rifle or carbine:

Colt Proof Marks between the FSB Legs
"12" approx 1" from the three prong or birdcage flashhider
Note: Early barrels were not chromed.

"Early" - C MP B
M = Magnetic Particle Inspected
P = Proof Fired
B = Chrome Bore
"Late" - C MP Chrome Bore

Per Colt all the SP-1 and GI chambers are the same. In the early 90's one of the members of the rifle time had a couple of SP-1's that he would not shoot M193 out of due to the .223 designation. We bet a steak dinner on it. He wrote Colt and based on their reply he bought me dinner. He also started shooting M193 out of them.

[Larry Gibson]

Mr. Gibson, I was hoping you would chime in, thanks so much! I do believe I have enough info to start load development after I decap and FL size this brass. One question remains unanswered; can I use the cases interchangeably with the same load data? Or did I miss that answer?:target_smiley:

For milspec duplication loads for use with ARs I don't segregate cases by manufacturer or by year (lot). Never found any increase or decrease in accuracy as any variation appears to be within the variable of ammunition and rifle capability. A match AR used for 300 - 1000 yard match shooting could use the segregation as can discerning bolt actions capable of sub moa accuracy. Accuracy these days is determined 80 - 90 % by the quality of the bullet. Getting wrapped around the axle in the other minutia is most often lost because the rifle/ammunition isn't capable of making any difference.

[Der Gebirgsjager]

Just an observation-- as recently as a year ago one could buy PPU, Igman, and Wolf in boxes labeled 5.56 mm or .223 Rem. Lately it seems like it's all labeled .223 Rem.

DG

[wwmartin]

When the 223 Remington XP100 varment special came out I just had to have one . He first ammo I fed it was PMC 5.56 factory. Round #17 extracted hard and had to be preyed from the bolt and I never found the primer. I was told at the time it was because I was using 5.56 not 223. I marketed a round and found rifling marks engraving about 1/16 on the bullet. I've been feeding it cast Lyman 55gr ever since.

Bill

[Bloodman14]

Mr. Gibson, Thank you, sir! I was leaning in that direction. Carry on, gents! Interested in how far this thread might go.

[Mk42gunner]

... Accuracy these days is determined 80 - 90 % by the quality of the bullet. Getting wrapped around the axle in the other minutia is most often lost because the rifle/ammunition isn't capable of making any difference.
This is true of so many cartridges, not just the .223/ 5.56mm.

Robert