Is there really a difference between .223 and 5.56 ammo?

[CavCop]

You have probably been told that you CAN NOT shoot 5.56 mm ammo in a .223 chamber safely, but you can shoot .223 ammo in a 5.56 safely.

I challenge that belief, and say the real difference in the ammo is 5.56 mm vs 5.56 mm NATO. Even in 9mm, NATO ammo is a hotter load. The FN based 62 Gr NATO round was the game changer.

What say you?

In this video I go over the history of the ammo.

 

[BRD@66]

Mindless robot that I am, I carefully use only .223 in my Mini 14.

 

[BeatTheTunaUp]

I don't buy .223 only guns. Problem.
solved.

 

[Tnhawk]

I don't buy .223 only guns. Problem.
solved.

That was my solution as well.

 

[leVieux]

Mindless robot that I am, I carefully use only .223 in my Mini 14.

<>

I’ve been told that some of the newer Mini14’s are marked “5.56”.

Same cast receivers ?

Does anyone here know?

?

 

[Bozz10mm]

Has anyone ever blown up a mini 14 using 5.56 ammo? I mean other than squibs or over charged handloads.

 

[CavCop]

Is y

Mindless robot that I am, I carefully use only .223 in my Mini 14.

Is your Mini 14 a Target Model? I think they are rated for only .223 Rem with only the Target model, but non NATO 5.56 on paper is .223 Rem and not 5.56 NATO.

 

[TrailerparkTrash]

I’ve always incorporated 5.56 NATO through my Mini-14’s when I got my hands on that ammo. If you look at Ruger manuals online, found on Ruger‘s website, all of their variant Mini-14’s (except the “target” model) explicitly say:

”The RUGER® MINI-14® RIFLES are chambered for the .223Remington (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. See “Ammunition Notice” & “Ammunition Warning”, below.”

Albeit it doesn’t say the word “NATO,” but it does say 5.56 and “standardized U.S. military OR factory loaded sporting 223 (5.56mm)…). I take that as being “NATO,” because that’s the military “standard.“

I’ve got 4 decades on one old Mini-14 and I lost count at the thousands upon thousands of 5.56 rounds I’ve fired through it, including NATO marked ammo.

 

[Mowingmaniac 24/7]

CavCop,

I really enjoyed your video, but then I would as I'm fairly knowledgeable gun guy.

Do I know the answer to your question: Ah, no...no I don't.

I've used most of the various military (surplus for me) ammo you discussed, but the most accurate I've found out my Colt LE 6920's 7:1 twist is the civilian 55 gr, 5.56x45mm NATO Federal American Eagle Ammunition XM193 Full Metal Jacket.

I've found all the military ammo that I've used that you mentioned to be accurate enough...2/3 inches at 50 yds.

One AR is a KISS, that is no mounted optics and the other is red dot mounted. Oddly enough, I shoot both with about the same accuracy at 50 yds. Perhaps because I'm no longer all that and more as a shooter I once was, but hey, I'm old and bent...

For me, 50 yds is about as far in a SHTF scenario...I think will be all I need.

Sorry for rambling...I'll subscribe.

 

[oldag]

<>

I’ve been told that some of the newer Mini14’s are marked “5.56”.

Same cast receivers ?

Does anyone here know?

?

I have read on more than one occasion that the Mini 14, according to Ruger, can use 5.56 safely.

 

[CavCop]

CavCop,

I really enjoyed your video, but then I would as I'm fairly knowledgeable gun guy.

Do I know the answer to your question: Ah, no...no I don't.

I've used most of the various military (surplus for me) ammo you discussed, but the most accurate I've found out my Colt LE 6920's 7:1 twist is the civilian 55 gr, 5.56x45mm NATO Federal American Eagle Ammunition XM193 Full Metal Jacket.

I've found all the military ammo that I've used that you mentioned to be accurate enough...2/3 inches at 50 yds.

One AR is a KISS, that is no mounted optics and the other is red dot mounted. Oddly enough, I shoot both with about the same accuracy at 50 yds. Perhaps because I'm no longer all that and more as a shooter I once was, but hey, I'm old and bent...

For me, 50 yds is about as far in a SHTF scenario...I think will be all I need.

Sorry for rambling...I'll subscribe.

There are many factors that come into play. The AR-15/XM16 was originally a 1:14 twist with a 55gr round (the .223 Rem and M193 were exactly the same back then). XM193 ammo today is not experimental surplus as with most X’s, but non Military ammo made using Military standards.

NATO ammo tends to have sealed bullets and primers (for wet conditions and to hold with full auto recoil and drops), and brass can be thicker (slightly less volume inside the case.

I can’t recall exactly the ranges, but the 55 Gr ammo is the most lethal of the military rounds. I know the magic FPS is 2700. I know a 20” M16 is effective (for the round to tumble and fragment) at 200 meters or less. With a 10.5” barrel it’s about 40-50 meters or less to be effective. The 16” to 14.5 is in between (like 150 meters to 100 meters max effective range for tumble/frag).

The SS109/M855 62 Gr NATO with 1/7 twist punches holes more than tumbles and frags. It was not as effective in combat as the 55 Gr M193. The M855A1 is more for penetration and consistency (along with being clean ammo). People wear more body armor and accuracy/penetration over injuries was a priority.

It is interesting the studies, myths, lore, history of the AR-15 and .223 Remington and what is has morphed into.

In 2008 we had good results with the Mk262 77gr hollow points in our M4’s, from Black Hills if I remember correctly.

 

[RankAmateur]

There are no differences in the dimensions between .223 Rem and 5.56 x 45 ammo (including 5.56 NATO) loaded with the same bullets. Some manufacturers load 5.56 hotter. The difference, and the safety recommendations, relate to the chambers.

5.56 chambers are cut looser than .223 Rem, and the throats of 5.56 chambers are typically also longer/looser than those for .223 Rem. This allows the cartridge walls to expand more, and allows the bullet to exit the case neck while the pressure is building. These differences permit use of higher pressures in 5.56 rounds without potentially "blowing up" the rifle. The leade of 5.56 chambers is supposed to be about twice as long as for .223. The looser cut chamber of 5.56 is actually not done to allow the case walls to blow out during firing (so lower peak pressure than in a tight chamber), it was designed to permit reliable feeding/extraction in dirty weapons. I would also submit that the actual chamber dimensions of various 5.56-chambered rifles vary between manufacturers, gunsmiths, and even age of the reamer used.

The tolerance for higher peak pressures in the chamber is relevant to standard or "thin" walled barrel chambers. I typically load .223 Rem match rounds with 80 to 90 grain .224 bullets, I load them very hot to produce muzzle velocities over 2800 FPS, and I load them with the bullets already jammed more than 10 thousandths into the rifling. I guarantee you that the peak pressures in my rifle are FAR above what are achieved with any 5.56 NATO rounds in Mini 14s or ARs, etc. My rounds are perfectly safe in my rifle as the barrel is 1.25 inches in diameter from the chamber all the way to the muzzle. If your rifle has relatively thin chamber walls, is old, is experiencing metal fatigue from LOTS of use, is made tighter by lots of carbon build-up, or anything else that would either weaken the chamber or increase peak pressures, you should be careful about restricting yourself to lower pressure rounds. Is it likely that a 5.56 NATO round will blow up a .223 Rem rifle? No, but not all rifles are equal, not all chambers are equal, and not all rounds are equal. Make informed decisions, be safe, have fun!

 

[Lonesome Dove]

Yes and No.
When you shoot a 5.56 from a braked 14" T/C it kinda rocks your world. But in the end all is good if you can still hear for the next few days.

 

[rotor]

There are no differences in the dimensions between .223 Rem and 5.56 x 45 ammo (including 5.56 NATO) loaded with the same bullets. Some manufacturers load 5.56 hotter. The difference, and the safety recommendations, relate to the chambers.

5.56 chambers are cut looser than .223 Rem, and the throats of 5.56 chambers are typically also longer/looser than those for .223 Rem. This allows the cartridge walls to expand more, and allows the bullet to exit the case neck while the pressure is building. These differences permit use of higher pressures in 5.56 rounds without potentially "blowing up" the rifle. The leade of 5.56 chambers is supposed to be about twice as long as for .223. The looser cut chamber of 5.56 is actually not done to allow the case walls to blow out during firing (so lower peak pressure than in a tight chamber), it was designed to permit reliable feeding/extraction in dirty weapons. I would also submit that the actual chamber dimensions of various 5.56-chambered rifles vary between manufacturers, gunsmiths, and even age of the reamer used.

The tolerance for higher peak pressures in the chamber is relevant to standard or "thin" walled barrel chambers. I typically load .223 Rem match rounds with 80 to 90 grain .224 bullets, I load them very hot to produce muzzle velocities over 2800 FPS, and I load them with the bullets already jammed more than 10 thousandths into the rifling. I guarantee you that the peak pressures in my rifle are FAR above what are achieved with any 5.56 NATO rounds in Mini 14s or ARs, etc. My rounds are perfectly safe in my rifle as the barrel is 1.25 inches in diameter from the chamber all the way to the muzzle. If your rifle has relatively thin chamber walls, is old, is experiencing metal fatigue from LOTS of use, is made tighter by lots of carbon build-up, or anything else that would either weaken the chamber or increase peak pressures, you should be careful about restricting yourself to lower pressure rounds. Is it likely that a 5.56 NATO round will blow up a .223 Rem rifle? No, but not all rifles are equal, not all chambers are equal, and not all rounds are equal. Make informed decisions, be safe, have fun!

Very well said.

 

[CavCop]

There are no differences in the dimensions between .223 Rem and 5.56 x 45 ammo (including 5.56 NATO) loaded with the same bullets. Some manufacturers load 5.56 hotter. The difference, and the safety recommendations, relate to the chambers.

5.56 chambers are cut looser than .223 Rem, and the throats of 5.56 chambers are typically also longer/looser than those for .223 Rem. This allows the cartridge walls to expand more, and allows the bullet to exit the case neck while the pressure is building. These differences permit use of higher pressures in 5.56 rounds without potentially "blowing up" the rifle. The leade of 5.56 chambers is supposed to be about twice as long as for .223. The looser cut chamber of 5.56 is actually not done to allow the case walls to blow out during firing (so lower peak pressure than in a tight chamber), it was designed to permit reliable feeding/extraction in dirty weapons. I would also submit that the actual chamber dimensions of various 5.56-chambered rifles vary between manufacturers, gunsmiths, and even age of the reamer used.

The tolerance for higher peak pressures in the chamber is relevant to standard or "thin" walled barrel chambers. I typically load .223 Rem match rounds with 80 to 90 grain .224 bullets, I load them very hot to produce muzzle velocities over 2800 FPS, and I load them with the bullets already jammed more than 10 thousandths into the rifling. I guarantee you that the peak pressures in my rifle are FAR above what are achieved with any 5.56 NATO rounds in Mini 14s or ARs, etc. My rounds are perfectly safe in my rifle as the barrel is 1.25 inches in diameter from the chamber all the way to the muzzle. If your rifle has relatively thin chamber walls, is old, is experiencing metal fatigue from LOTS of use, is made tighter by lots of carbon build-up, or anything else that would either weaken the chamber or increase peak pressures, you should be careful about restricting yourself to lower pressure rounds. Is it likely that a 5.56 NATO round will blow up a .223 Rem rifle? No, but not all rifles are equal, not all chambers are equal, and not all rounds are equal. Make informed decisions, be safe, have fun!

Yes the 5.56 chamber throats are 0.125” longer and the ‘forcing cone’ angle/tapers are different too.

Why the Wylde chamber (and later Novaseke) came in to bridge the gap, kind of like the 1:8 twist to blend the 1:9 Vs 1:7.

 

[rotor]

Yes the 5.56 chamber throats are 0.125” longer and the ‘forcing cone’ angle/tapers are different too.

Why the Wylde chamber (and later Novaseke) came in to bridge the gap, kind of like the 1:8 twist to blend the 1:9 Vs 1:7.

For the average person the safe thing is that if the barrel is marked 5.56 than .223 Remington or 5.56x45 is safe.

 

[RankAmateur]

Why the Wylde chamber (and later Novaseke) came in to bridge the gap, kind of like the 1:8 twist to blend the 1:9 Vs 1:7.

5.56 Wylde chamber is often even a bit looser than 5.56 x 45, except for the throat. The "accuracy" differences commonly associated with the .223 vs 5.56 ammo/rifles are largely related to how tightly controlled the bullet is as it leaves the case mouth and "jumps" to the lands. 5.56 throats are generally "sloppier" so the bullet has the chance to skew or misalign with the bore on the way to the rifling. Bill Wylde's design tightened up the throat diameter around the freebore so the bullet is kept straighter (as it is with .223 Rem). So, 5.56 Wylde (for example) permits reliable feeding of dirty weapons, use of higher pressure rounds (like 5.56 NATO), AND increased precision than typical 5.56. As with all designs, it has it's own compromises. (Generalization warning ahead ) 5.56 Wylde is not as precise as .223 Rem due to the looser/"sloppier" chamber, is more precise than 5.56, and despite being as safe/safer than 5.56 NATO chambering is NOT safe for use with intentionally "hot" loads (like the match load I described above) regardless of whether the load is .223 Rem or 5.56 x 45.

 

[zackmars]

There's a pressure difference, if you put a legit 5.56 in a .223 chamber.

The hard part is finding real 5.56. just because the box says 5.56, doesn't mean it is. The last real 5.56 on the market was IMI brown box. That stuff killed more than a few .223 guns, or improperly cut 5.56 chambers.

Unfortunately people went after the ammo mfg's instead of the companies who couldn't figure out how to ream a 5.56 chamber even if it meant INS would stop raiding them.

 

[BRD@66]

Is y

Is your Mini 14 a Target Model? I think they are rated for only .223 Rem with only the Target model, but non NATO 5.56 on paper is .223 Rem and not 5.56 NATO.

Not target model. Manufactured circa 1975-1976. Marked .223.
Mine is the troublesome, low serial-numbered 182 series.

 

[Maxrobot]

Has anyone heard of a set of no-go gauges for .223 vs 5.56mm? I imagine that commercial barrel makers use the same reamer for both. Would some shop actually change reamers when making an AR-i5 vs bolt action gun?
If there are any barrel makers out there, please chime in.