Ammo: 556 vs. 223

[navycraig]

Disclaimer: I'm new to the AR platform and have recently picked up my first; a Ruger SR-556.

If given a choice between shooting 556 or .223, which do you prefer and why?
I was told by one guy that 556 was basically .223 leftovers, but I don't buy that.
Another guy told me that the big difference is that 556 carries more pressure and is therefore faster / flatter shooting.
A local shop has both in stock for the same price...$9.99 per box with a 10% discount for 10 boxes or more.

 

[Baccusboy]

Google is your friend:

http://www.humanevents.com/2011/02/15/223-remington-vs-556-nato-what-you-dont-know-could-hurt-you/

 

[Maverick0313]

Google is your friend:

http://www.humanevents.com/2011/02/15/223-remington-vs-556-nato-what-you-dont-know-could-hurt-you/

Great answer and good post!!!!

 

[Redcobra]

Is the gun chambered for 5.56? If so shoot both and see what you like.
If not...steer clear of 5.56. It'll be marked on the barrel.

 

[navycraig]

Google is your friend:

http://www.humanevents.com/2011/02/15/223-remington-vs-556-nato-what-you-dont-know-could-hurt-you/

Yeah, I did the google thing and read all of that so I guess I could have left out the question on pressure since it is answered.
However, I asked what you would shoot and why because I trust the members on here much more than I do google sources. Thanks for the link though.

Is the gun chambered for 5.56? If so shoot both and see what you like.
If not...steer clear of 5.56. It'll be marked on the barrel.

Ruger SR-556 so yes, chambered in 5.56. I have shot both and can't tell a distinct difference, which again, is why I asked for input from MDS members.

Thanks.

 

[Mooseman]

I shoot either or. Which ever one I have or can find. I do not have a true preference.

 

[kohburn]

some myths and theories put to the test

http://www.luckygunner.com/labs/5-56-vs-223/

a very good read for EVERYONE who uses these calibers.

 

[dev]

Good articles but it still has me begging for questions unanswered.

I have been told various things and even I don't know if they are correct.

1. What I have been told is that 5.56 is the standard for the military because it makes the rifle more reliable having a looser fitting chamber then a dedicated .223 barrel. I have also been told it's the standard by which NATO sets.

2. They say that the 5.56 brass shell is thicker having less internal volume therefore more pressure using less powder then .223. However re-loaders say you can mix both shells by trimming of the cases and setting the bullet depth as that is all that matters which is completely contradictory.

3. Why would they mark some barrels 5.56 if it is not designed for that cartridge. Are they inviting a lawsuit and why is there no awareness of which barrels to stay away from.

4. I have been told by one ammo manufacture that .223 is better for accuracy because it is loaded to SAMI specification which is more precise.

My own personal observations is that 5.56 is flatter and has more kick. I have not noticed anything different in terms of accuracy between the two rounds.

 

[Crxflippr]

Ruger SR-556 so yes, chambered in 5.56. I have shot both and can't tell a distinct difference, which again, is why I asked for input from MDS members.

Thanks.

At 100 yards and iron sights, I can't tell much of a difference. Which ever is cheaper and/or cleaner.

 

[kohburn]

read the entire article i posted - it has at least a comment if not an answer to all the questions you asked.

essentially - 5.56 nato is military standard, 223 saami is commercial standard

even among those the chamber dimensions vary (see the reamer dimnsion chart)

the final result is other than the 223 wylde - you can use 223 556 universally among 223 556 chambers with the worse issue being popped primers.

 

[bkuether]

Yeah, I did the google thing and read all of that so I guess I could have left out the question on pressure since it is answered.
However, I asked what you would shoot and why because I trust the members on here much more than I do google sources. Thanks for the link though.


Ruger SR-556 so yes, chambered in 5.56. I have shot both and can't tell a distinct difference, which again, is why I asked for input from MDS members.

Thanks.

The 5.56 is a more powerful round. And I can tell the difference. I am also a relative noob to the AR world. When I shot my Stag 8 the first time with some 223, I was like , yeah hardly any recoil. 5.56 was different experience. Wasn't "BAD" by any means but you can tell. Now some if it may be due to the piston configuration. I won't know until I get my Core 15 DI back from my "three hour tour". The other thing I have noticed is that 223 comes out of my barrel a little squirrelly. From what I have been told, the 1:7 is better for heavier, more powerful rounds. The 223 tends to fly high and to the left for me anyway.

 

[Deep Creek Rock]

Here is an intresting wiki article fyi:

.223 Remington versus 5.56 mm NATO

While the 5.56mm NATO and .223 Remington cartridges and chamberings are very similar, they are not identical


While there is a myth that 5.56 NATO cases are thicker and hence have less capacity than commercial .223 cases, this has been shown to be false. Each brand of case and each manufacturing lot has a slightly different case capacity; 5.56 NATO and .223 commercial cases tend to have nearly identical case capacity when measured using the water test.[6] The NATO specification allows a higher chamber pressure. NATO EPVAT test barrels made for 5.56mm NATO measure chamber pressure at the case mouth, as opposed to the location used by the United States civil standards organization SAAMI. The piezoelectric sensors or transducers NATO and SAAMI use to conduct the actual pressure measurements also differ. This difference in measurement method accounts for upwards of 137.9 megapascals (20,000 psi) difference in pressure measurements. This means the NATO EPVAT maximum service pressure of 430 megapascals (62,000 psi) for 5.56mm NATO, is reduced by SAAMI to 379.21 megapascals (55,000 psi) for .223 Remington.[7] In contrast to SAAMI, the other main civil standards organization C.I.P. defines the maximum service and proof test pressures of the .223 Remington cartridge equal to the 5.56mm NATO.

The 5.56mm NATO chambering, known as a NATO or mil-spec chamber, has a longer leade (also referred to as the throat), which is the distance between the mouth of the cartridge and the point at which the rifling engages the bullet. The .223 Remington chambering, known as SAAMI chamber, is allowed to have a shorter leade, and is only required to be proof tested to the lower SAAMI chamber pressure. To address these issues, various proprietary chambers exist, such as the Wylde chamber (Bill Wylde)[8] or the ArmaLite chamber, which are designed to handle both 5.56mm NATO and .223 Remington equally well. The dimensions and leade of the .223 Remington minimum C.I.P. chamber also differ from the 5.56mm NATO chamber specification.

Using commercial .223 Remington cartridges in a 5.56mm NATO chambered rifle should work reliably, but generally will not be as accurate as when fired from a .223 Remington chambered gun due to the longer leade.[9] Using 5.56mm NATO mil-spec cartridges (such as the M855) in a .223 Remington chambered rifle can lead to excessive wear and stress on the rifle and even be unsafe, and the SAAMI recommends against the practice.[10][11] Some commercial rifles marked as ".223 Remington" are in fact suited for 5.56mm NATO, such as many commercial AR-15 variants and the Ruger Mini-14, but the manufacturer should always be consulted to verify that this is acceptable before attempting it, and signs of excessive pressure (such as flattening or gas staining of the primers) should be looked for in the initial testing with 5.56mm NATO ammunition

 

[deercrazy82]

Which shop had the 556 ammo for sale?

 

[outlaw]

both should work, which does your rifle like? it's great luck that you can find some ammo in stock!

 

[Kilroy]

My gun prefers XM193.

 

[BradMacc82]

All of my AR's are chambered for 5.56, but I honestly haven't noticed too much difference between the two. 5.56 does have a (slightly) stronger felt recoil than .223 (to me anyways), but the .223 rounds seem to be slightly more accurate - especially when compared to 62gr green-tips, which isn't bad to begin with, but the 55gr FMJ-BT does give ME tighter groups.

Honestly, I'd stack up whatever you can find/buy.

For my own AR's, I reload. The accuracy I've gotten out of handloads has kept me from buying commercially loaded rounds, and the price if I'm honest.

 

[TimGB]

.223 also seems to be cheaper from what I have seen. Before the recent ammo shortage, brass .223 could routinely be found for 30-35 cents/round. I never found 5.56 that cheap.

I always thought of 5.56 as "better" based on what I had heard/read, but based on the article posted, I'm not sure that is entirely true.

 

[Robert Avery]

I would find the Brand and weight of Bullet that is the most accurate out of your rifle and stick with it. Keep your Brass sorted and use the same Head stamp when reloading and you should be good to go. Check your mags as well as certain Brands limit the OAL to short for some Bullets and will compress your load beyond 10% which will eventually walk out when left for a period of time. 5.56 has a longer neck and was designed for higher pressures than the 223 so it would be safe to use only the same Head stamp so that your crimp is in the right place.

 

[montoya32]

Do 5.56 barrels have a different twist rate than .223 barrels?

 

[Chevy]

A local shop has both in stock for the same price...$9.99 per box with a 10% discount for 10 boxes or more.

Name of shop?