Help 223?

[Rooster2]

Some years ago I purchased a Ruger AR-556 from our local FAD. When I did so I remember asking for and about the 223? Any way long story short the barrel is stamped 5.56 NATO 1-3. I have always fired 223 in this rifle, but now curious to know if it really is chambered for the 5.56? And is 1-3 the twist?

[FoghornLeghorn]

You can fire 5.56 NATO or 223 in that rifle.
Twist is 1:8

[rickyrick]

Yes 1:8 is more plausible.

Most are 1:7, 1:8 or 1:9

[mehavey]

> Equipped with a medium contour, cold hammer-forged alloy barrel
> with 1:8" twist rifling that provides exceptional accuracy with bullets
> from 35 to 77 grains. M4 feed ramps and 5.56 NATO chamber allows
> the use of both 5.56 NATO and .223 Rem. ammunition. The barrel
> and 1/2"-28 Ruger® flash suppressor have a matte black oxide finish
> to reduce glare and provide corrosion resistance.
https://ruger.com/products/ar556/specSheets/8500.html

[Rooster2]

Thank you for the info....

[paknheat]

I’m supposing that the 1-3 is really a 1-8. Maybe the 8 didn’t come through very well when they marked the barrel.


Sent from my iPhone using Tapatalk Pro

[Rooster2]

I have to assume the same thing...

[Shadow9mm]

5.56 and 223 cartridges are the same size. 5.56 is rated at a higher pressure than 223. You can shoot 223 or 5 56 in a 5.56 gun. Either should shoot just fine in your gun. As stated twist is most likely 1:8.

[mehavey]

5.56 is rated at a higher pressure than 223

Actually not. The European CIP system measures the pressure at a different points and w/ different methods.
https://ultimatereloader.com/2018/08...cts-and-myths/

Throat, and not pressure, is the 5.56 difference.

[Rooster2]

I found this video to be very helpful....
https://youtu.be/VCS4fXFmCyA

[Shadow9mm]

Originally Posted by mehavey

Actually not. The European CIP system measures the pressure at a different points and w/ different methods.
https://ultimatereloader.com/2018/08...cts-and-myths/

Throat, and not pressure, is the 5.56 difference.

So many people put too much stock in the measurement location. My understanding has always been that the point of measurement is a factor used in calculating the pressure, not an actual direct measure of pressure in the cartridge itself. Much like measuring wheel horse power vs the hp at output shaft. Thus, max pressure is max pressure.

[mehavey]

max pressure is max pressure

Not necessarily.
When measured the same way, 5.56 Pressure ~ same as 223 pressure.

Search the referenced article for these exact words:
"The conclusion: 223 Remington and 5.56 NATO have essentially the same maximum working pressure rating."
Read the measurement method.

[Joe-ker]

Yes it’s 1-8 twist

[Shadow9mm]

Originally Posted by mehavey

Not necessarily.
When measured the same way, 5.56 Pressure ~ same as 223 pressure.

Search the referenced article for these exact words:
"The conclusion: 223 Remington and 5.56 NATO have essentially the same maximum working pressure rating."
Read the measurement method.

"ESSENTIALLY" is not the same as.

55,000 vs 58,000
are the pressure ratings

if you allow for testing points
55,00 vs 55,114

but they are not the same, and this does not take chamber variances into account. They are measured in their own chambers, not each others.

here is another good article with testing worth a read, showing 5.56 in a 223 chamber can be between 55,000 to 65,000 psi.

https://ballistictools.com/articles/...-and-facts.php

[mehavey]

In your article above...
>
> "While the specified pressures of 5.56 and .223 are the same,
> the pressures are measured when they are fired from the correct chamber."
>

If I incorrectly jam a 223 into the leade/rifling, it's going to raise pressures.
Firing the cartridge in the wrong chamber is not the same as that cartridge being loaded to a higher pressure.
You -- the shooter -- have caused the higher pressure through error. Not the cartridge.

Fired in compatible chambers, the two are effectively the same pressure.

.

[Shadow9mm]

Originally Posted by mehavey

In your article above...
>
> "While the specified pressures of 5.56 and .223 are the same,
> the pressures are measured when they are fired from the correct chamber."
>

If I incorrectly jam a 223 into the leade/rifling, it's going to raise pressures.
Firing the cartridge in the wrong chamber is not the same as that cartridge being loaded to a higher pressure.
You -- the shooter -- have caused the higher pressure through error. Not the cartridge.

Fired in compatible chambers, the two are effectively the same pressure.

.

SMH....

223 and 5.56 are not the same. They are 2 different cartridges. While the cartridge dimensions are the same, and the working pressure are similar, in their respective chambers, they are defined by the chamber they are fired in, not the cartridge itself.

thus, as noted in the article I linked. Firing a 223 in a 5.56 chamber can result in reduced pressures, and firing a 5.56 in a 223 chamber can result in higher and possible unsafe pressures.

the listed working pressures are only correct in the proper chamber.

[mehavey]

...the... working pressures (which are in fact ~55ksi each when measured the same) are only correct in the proper chamber.

I rest my case.

[Sweet Shooter]

@Shadow9mm - "223 and 5.56 are not the same. They are 2 different cartridges."
Wrong. Be clear. You're contradicting yourself in the next sentence. I know you know this, because your second sentence is correct.

ERGO: .223 and 5.56 are the same cartridge case. It's the chambers that differ. The 62gr M855 (NATO 5.56) and M856 projectiles (or any other long-for-caliber projectiles) are the rounds that can create potential issues if fired in the .223 chamber.

[rickyrick]

Has anyone ever experienced issues from shooting 5.56 in a.223 rifle?

I’ve not ever tried it because the hive agrees that .223 in a 5.56 is ok but the reverse is not.

I just simply followed directions from others.

However, I’ve never seen one thing where someone says their gun was damaged by doing it.

Not saying that I’m a nonbeliever, but I haven’t personally heard, read an account of or witnessed anything myself. But my circle is small.

[jmr40]

Has anyone ever experienced issues from shooting 5.56 in a.223 rifle?

Before the internet they were interchangeable.

Yes, there are VERY minor differences in the max allowable pressures and VERY minor differences in chamber specs between the two. 5.56 is the military designation, 223 the civilian designation. The military specs slightly looser chambers for reliability and slightly higher pressures are allowed.

BUT...

The differences are so small that you'll actually see greater differences with varying tolerances with most any cartridge. I like to use 30-06 as an example. If you compare 30-06 loads and chambers over the years you more likely to find some factory 30-06 loads that will cause you problems in some 30-06 chambers than you will when firing 5.56 in a 223 chamber.

With 30-06 semi-autos like the Garand you have to keep the ammo within a fairly narrow pressure range for function and to avoid breaking the rifle. There are a lot of factory 30-06 loads not suitable for semi-autos. But they still label them all 30-06, you just have to know which ones not to use.

Bolt rifles however will handle all pressure levels available in 30-06. But it is still possible to find chambers in some bolt rifles cut to minimum tolerances that won't chamber some factory loads manufactured to max allowable tolerances. That is true with all cartridges. While rare, it does happen.

The only real-world issue with shooting 5.56 in a 223 chamber is unreliable feeding and possible excessive wear in a semi-auto 223. But to my knowledge the only semi-auto 223 ever made were the very early Mini-14's. They went to 5.56 chambers years ago.

People shoot 5.56 in 223 bolt rifles all of the time with no more issues than they find firing 30-06 in 30-06 bolt rifles. That isn't to say that issues don't come up, but you see those same issues with any other cartridge.

[44 AMP]

Some how the idea has taken root that what is a difference in pressure is automatically a DANGEROUS difference in pressure, and in this case, that is simply not so.

Guns are not made of glass, and considering the fact that there must have been more than a few people who fired the "wrong" ammo where are all the stories of blown up rifles from doing that???

My point here is that the rifles are proof tested to significantly higher amounts, and survive without damage.

What is essentially a minor overpressure by the standards of "working pressure" should not damage any firearm worth owning.

If it does, then I'd say you chose your purchase poorly.

[mehavey]

The 223 and the 5.56 operate at the same pressure, when measured in the same way.

("Boom!". . . as my son would say)

Any potential issue comes to bear when certain 5.56 loadings use some specific military bullets -- loaded at specific lengths -- which impinge (contact) 223-specific throat profiles.

. . . raising pressures above "...nominal." **

**

Before the internet they were interchangeable.

[Scorch]

Oh, wow. Somebody's having the 5.56/223 discussion. Again.

A little bit of research will show that they are in fact the same cartridge, Remington released the .223 Remington after helping in the design of the new cartridge for the M16 (designed to give higher velocity and be the same COAL as the original 222 Remington so the AR-15 forgings would not have to be scrapped or modified). There is a looser tolerance in chamber dimensions for military weapons (full auto fire/carbon accumulation/field conditions), and the throat is different to allow for the shorter ogive/heavier bullets the military wanted to use to give steel helmet penetration at 500 yds.

Have there been accidents involving firing 5.56X45 in 223 chambered rifles? I have read reports but never seen one in 30 years of gunsmithing. Could there be a problem firing 5.56 in a 223 chamber? Sure. There can be problems firing 223 in a 223 chamber as well, not all caused by chamber/throat dimensions.

Kind of a long-winded way to say give it a rest.

[Sweet Shooter]

@scorch:
"Kind of a long-winded way to say give it a rest."

Ha ha... yes. Just don't tell the kids they can put M855 or M856 in a .223 chamber. It isn't a good idea generally. XM193 (55gr 5.56) however is unlikely to cause issues though.

[bamaranger]

A few years back, seems like a made a post about firing a 5.56mm ctg in my Mini-Mauser Mk-X bolt rifle stamped .223. I'd done that before, I'd had the little rifle 20 years, and am really quite fond of it. On occasion I'd shoot some 5.56mm stamped FMJ through it. But I won't ever do it again.

In this particular instance, I had recently acquired a chronograph, my first one. I ran may pet reload for the Mini-X, a near max load using a 52 gr bullet. I was surprised at the low velocity, well below what my manual listed. Heck......the stuff ya learn, right? Then I ran a 5.56mm FMJ with NATO head stamp..........WOW! I don't recall the numbers, but it was screaming, like 200-300 fps faster than my reloads. Extraction was good, case/primer looked OK, but the numbers suggested that pressure jump was significant.......no more.