Does .223 Equal 5.56?

[RaySendero]

Oddly I can't find any conversion factor that makes .223 or .224 inches equal 5.56 mm! Always comes out 5.66 or 5.68.

Guy - Think the prob your having doing the math is that the .224" is the groove diameter and the 5.56 mm is the bore diameter.

[rickt300]

My first 223 was a Remington 788.  It would blow primers with military 5.56 ammo and wouldn't stabilize the 55 gr. FMJ.  I pulled the bullets, replaced them with 50 gr. Hornady SX bullets and had good ammo.

[Hank08]

PASTORP, if your shooting 762X54 interchangably with .308 Win, your the one that's FUNNY.
H08

[SHOOTALL]

There is an article this mo. in HANDLOADER mag. that addresses this issue . It says they are almost idenical except for head space . Military chambers have longer headspace dem. . This applied to both 308/ 7.62X51 and .223 / .556
Just passing it along

[2ndtimer]

PASTORP, if your shooting 762X54 interchangably with .308 Win, your the one that's FUNNY.
H08

Yeah, Hank and I would like to see PASTORP (or anyone else, for that matter) get a 7.62x54 Russian rimmed cartridge into a .308 Win. chamber!

[jro45]

I was saying mouth meaning where the bullet seats, Gradbeard.

[SHOOTALL]

The chamber of a bbl marked 5.56 has more freebore ( longer chamber ) than a standard .223 rem bbl. in battle the gun may fire 100's or maybe 1000's of rounds before cleanning , also you would not want a bbl. with such a tight chamber that dirty or slightly out of spec. ammo would not function where in a hunting rifle conditions are not as despert . The primer of a 5.56 is of thicker metal and resist the slap of the fireing pin on bolt closing (slam fire ) . Anyone who has a new M1-A got a notice with the gun advising the same comdition with regard to 308 win vs. 7.62X51 ammo.
 Also the shape of the bullet can affect feeding in some guns marked 5.56 as military ammo meets a standard to shape of bullet where commerical ammo takes many shapes .
7.62X39 uses a .310-. 312 dia. bullet depending on manf. and country of org. Some loaded in the USA is loaded with a .308 bullet and the Ruger mini 30 had a bbl. of .308 . Most if not all other rifles use the larger bore and are not as accurate with .308 bullets . The britt 303 and jap 7.7 are other examples of the larger bore .

[emsemt911]

I have to put my inpout on this subject.

You can shoot .223 in a 5.56.
You can NOT shoot 5.56 in a .223 Rem.
Because of this, you will see gun barrels that say 5.56/.223 Rem.
You will also see .223 Rem.  DO NOT SHOOT 5.56 in this marking.



SAAMI, who sets the standards for bullets.
It shows the difference in the rounds.

Posted already by a previous member:
 http://www.saami.org/Unsafe_Combinations.cfm

If a problem does occur when you shoot a 5.56 in a .223 rem barrel, and it will, you will not be able to get warrantee repairs. Anyway, I find .223 Rem more accurate ammo.

[Swampman]

I've fired many of both in rifles marked both ways with no problems.

[mechanic]

I've shot thousands of rounds of milsurp 5.56 in a Ruger mini 14 some years ago.  Lucky to keep them in a 9" pie plate, but they never failed to feed or fire.  We shot them up instead of pulling bullets for the brass......

[Swampman]

Isn't that about right for a Mini-14?

[mechanic]

Isn't that about right for a Mini-14?

Yep, it shot everything that way, from cheapo to reloads.  It sure was not a target rifle, but it never failed to spit out a bullet when called upon.  I sold it a few years ago, and replaced it with an SKS, which is far more accurate......

[securitysix]

I've shot thousands of rounds of milsurp 5.56 in a Ruger mini 14 some years ago.  Lucky to keep them in a 9" pie plate, but they never failed to feed or fire.  We shot them up instead of pulling bullets for the brass......

The manual for the Mini-14 does actually say you can shoot 5.56 ammo in it, so that's not a big deal.

The 5.56x45mm NATO cartridge has to meet a particular velocity with a particular bullet design (M855 = 62 grain SS109 projectile at 3100 FPS).  The loads the military uses to do this can create excessive pressures in a .223 Remington chamber.  Because of this, the 5.56x45mm NATO chamber has a longer throat than a .223 Remington chamber.  M193 is not actually a NATO cartridge, but it must be treated similarly to M855 with regards to which chamber it is fired in.

.223 Remington cannot exceed a particular maximum pressure, regardless of what velocity it makes, and regardless of bullet weight and/or shape.  .223 Remington is safe to fire in the 5.56x45mm NATO chamber, although some may be underpowered and not cycle the action reliably (Wolf is considered to be notorious for this, but most .223 Remington ammo should be fine). 

There is also a .223 Wylde chamber.  The Wylde chamber has a shorter throat than the NATO chamber, but a longer throat than the .223 Remington chamber.  It will fire both 5.56x45mm NATO spec ammo and .223 Remington ammo safely.  The purpose of the Wylde chamber is to give better accuracy (due to the shorter throat) with 5.56x45mm NATO ammo.

[emsemt911]

if this is not a big deal, why do manufactuers twll you that shooting 5.56 can void thw warantee in a .223?

[bcp]

No they are not interchangeable.
http://www.saami.org/Unsafe_Combinations.cfm

Has anyone read that whole list?  It looks like it was written for the idiot that would jam anything in his rifle that will fit in it.  Honestly, who sticks a 20 ga. shell in a 12 ga shotgun and expects it to work?  And how the heck do you even get a 44 mag in a 45 auto pistol?

I would like to know what happened to deserve this warning:

In Rifle Chambered For ...............Do Not Use These Cartridges

300 Savage.................................338 Winchester Magnum

[DC]

I have owned both AR's and Mini 14's.  I just bought a Mini 14 Target which with good ammo shoots MOA of less.  Some guys are getting well below MOA with it.  As to the difference between 5.56 and.233, If you look up all case sizing information you can find, they are identical.  If you contact most rifle manufacturers, they will tell you that they chamber their rifles to shoot both.  Before I put down the $860 for the Target model, I called Ruger.  I was fortunate enough to speak to someone other than the nice girl that answers most of the questions.  What I was told that any Ruger would function safely with 5.56's as well as .223s.  My experience with 5.56 in my Savage varmit, my older Mini and now my new Mini is the same.  I don't have any function issues with brass shells but have had a couple of flat primers with Wolf steel case ammo.  That I think is more of a Wolf ammo thing than anythink else.  ...inconsistancy.
I think that it is interesting as someone else said, that SAMI would wait 40 years to decide that shooting 5.56 rounds in 223 rifles is not ok.  Makes you wonder abount the boys and girls that make those decisions.

If anyone thinks that their AR which says 5.56 on it has a stonger action, beefier chamber etc. than a Mini 14 or almost any bolt .223 rifle, well I have a bunch of really cool things for sale that I am sure you would love.  The preponderance of the posts here would indicated that shooting one in the other is perfectly ok.

[helotaxi]

If anyone thinks that their AR which says 5.56 on it has a stonger action, beefier chamber etc. than a Mini 14 or almost any bolt .223 rifle, well I have a bunch of really cool things for sale that I am sure you would love.  The preponderance of the posts here would indicated that shooting one in the other is perfectly ok.

The reality is that the two rounds are not the same.  .223 Remington is a commercial cartridge with its dimensions and pressures laid out by SAAMI.  5.56 NATO is a military cartridge and as such does not fall under the purview of SAAMI.  The cartridge dimensions are the same, what is not the same is the loading pressure or the chamber dimensions.  The NATO round is loaded hotter.  5.56 and .223 max loads fired in a 5.56 chamber will show around a 5000 CUP difference in pressure.  The NATO chamber also has a longer, shallower leade which keeps the bullet from abruptly hitting the lands causing a larger spike in pressure.  If you were to fire the same two 5.56 and .223 rounds in a .223 chamber, the difference in pressure would be significantly higher and well beyond normal safe limits.

The strength of the chamber and bolt has nothing to do with why one gun is safe with 5.56 and another is not.  The contour of the chamber has everything to do with it.

[bcp]

Times have changed!

I have a collection* of articles from Rifle and Handloader magazine.  There is an undated article on the 223 written by Bob Hagel.  The first three paragraphs are about the lower pressure military cartridges, required for the M16 and AR15,  and how reloading to bolt action rifle pressures can significantly improve the cartridge's performance.

*Varmint and Small Game Rifles and Cartridges
Wolfe Publishing Co. 1993


Bruce

[huntducks]

You guys kill me. Old wives tales and folk lore.

You should listen to Bill, he has it right...................I've shot military 7.62x54 interchangeabely with .308 winchester rounds in military and civalian guns for years. Done the same thing with 5.56 and 223. You guys are really funny.

Regards,

+1 on what you said.

The internet can be a good thing but it sure has spread some pi$$ poor info.

I have been inter changing both 308> 7.62x54 and 223 > 5.56 for years.

I think one of the biggest problem is this cheap pi$$ poor specks out of the country cheap ammo, I bought some 30 carb import stuff 15 years ago decided to open the 1200 tin and shoot some, 6-7 shots in the botton of the case at the rim opened up blew gas out the bolt glad I had shooting glasses on as I had flecks of powder all over my face, I thought the bolt did not close all the way so every I started to take a shot made sure the bolt was slamed closed and it happened again first time I did not slam the bolt closed,I stopped shooting that ammo and went back to reloads , when I got home I pulled every case apart of the 50 rds I had and 3 remaining where 2grs over powder wise I decided to buy an Elec scale and weight every round (that was fun) but I was able to cull out everything that was not close after closer inspection and pulling apart there was 5 rounds per box that were over charged and the case were larger Dia. around at the base and rim not much but enought not to notice and enought not to let the bolt rotate and lock up.

I can only assume the 5 rounds in ea box came from a different source reloading machine on there line.

I don't buy any cheap import sh!! any longer and don't shoot any of the 1200 rounds in my GI Carbine but my Ruger 30 carb SS they work just fine.

[nomosendero]

I am amazed how this keeps getting kicked around!!

[alsaqr]

The NATO round is loaded hotter.

This is a SAAMI myth:

Got to page 10-3 and find out that the 5.56mm M193 round generates 52,000 psi.  

http://www.scribd.com/doc/13027441/ammo-data-sheets-small-caliber-firearms

If you were to fire the same two 5.56 and .223 rounds in a .223 chamber, the difference in pressure would be significantly higher and well beyond normal safe limits.

This is not true either:  It is another SAAMI myth.  A friend has an Oehler model 43 personal ballistics lab.  He measured the pressure of military M193 and M855 ball rounds fired in the chamber of his .223 Remington model 700 rifle.  Pressure never exceeded 60,000 psi.  


Ask yourself why it took SAAMI 30 years to come up with their spiel about how dangerous 5.56mm ammo is when fired in a a .223 chamber.  This is the same SAAMI who asked the ATF to come up with standardized regulations for the shipment and storage of small arms ammo and reloading components.  The ATF did that: SAAMI immediately went about getting the draft regulation declared null and void.  SAAMI lied, cried and got uninformed gun owners to back their lies by writing to their congressmen.    

There are presently 12-15 different .223/5.56mm chambers.  

[helotaxi]

This is not true either:  It is another SAAMI myth.  A friend has an Oehler model 43 personal ballistics lab.  He measured the pressure of military M193 and M855 ball rounds fired in the chamber of his .223 Remington model 700 rifle.  Pressure never exceeded 60,000 psi.

Which is 7k over pressure.

[Swampman]

They are interchangeable.

[diggler1833]

I've got a bit of experience with both.  I'll fire .223 in a 5.56 chamber, but not the other way around.  You CAN get away with 5.56 in a .223, but possibly not forever, I'll keep my risks to a minimum.

For conversation purposes I'll do 7.62 in a .308 though.

I wonder how many more angles can be presented on this?

[mechanic]

Sounds like every angle has been covered most definitively pro and con and everyone is right!

[DC]

I know that this is an old thread but having purchased a Mini 14 Target I was curious about the difference.  The owners manual says you can fire either in all their Mini's except the Target Model, which I have.  Wondering why and wanting to hear from the horses mouth so to speak, I emailed Ruger and phoned as well.  I was told that there is a slight chamber difference between 223 Rem. and 5.56.  They did not say it wouldn't work but shooting the 5.56 in a target model is not recommended. 

That really isn't a problem because I have 1000+ of 223's.  I don't see any reason to buy any Lake City military rounds anyway as there is not a big difference in cost.  In a SHTF situtation I would use anything I could find but since the choice is there why not just shoot .223's?

By the way my new MIni Target is shooting sub MOA with less than premium ammo.  I have a Weaver Grand Slam on top, 6-24x44 which helps 

[Lloyd Smale]

me too. To me its just an argument people who like to think they know it all use to make themselves look knowlegable. Ive yet to see a gun that wouldnt fire both.

I've fired many of both in rifles marked both ways with no problems.

[MGMorden]

me too. To me its just an argument people who like to think they know it all use to make themselves look knowlegable. Ive yet to see a gun that wouldnt fire both.

Yep.  My AR is marked as 5.56 NATO so I assume it's safe for the military round and .223.  Someone on another board was asking about it recently and they called Savage (their .223 was of Savage make) and the phone rep said it was absolutely fine to fire 5.56 NATO in their rifles marked .223 Winchester.  I don't know.  Maybe it's different in some semi-autos, but even if you concede that the pressure is a LITTLE higher on 5.56 NATO, many of the bolt guns are the same actions used to fire even higher pressure rounds with ease. 

[Oldshooter]

This thread proves that no matter where ya go ..........there ya are! 

If you want controversy just post sumpin on the internet for public comment!

[STRANGE1]

the phone rep said it was absolutely fine to fire 5.56 NATO in their rifles marked .223 Winchester.

Problem solved.  just find one marked .223 winchester and shoot whichever you want in it.  

this is the best explanation i have read yet.

While the external case dimensions are very similar, the .223 Remington and 5.56x45mm differ in both maximum pressure and chamber shape. The maximum and mean pressures for some varieties of the 5.56 mm (different cartridge designations have different standards) exceed the SAAMI maximums for the .223 Remington, and the methods for measuring pressures differ between NATO and SAAMI.[5] The 5.56 mm chamber specification has also changed over time since its adoption, as the current military loading (NATO SS-109 or US M855) uses longer, heavier bullets than the original loading did. This has resulted in a lengthening of the throat in the 5.56 mm chamber. Thus, while .223 Remington ammunition can be safely fired in a 5.56 mm chambered gun, firing 5.56 mm ammunition in a .223 Remington chamber may produce pressures in excess of even the 5.56 mm specifications due to the shorter throat.

i seriously doubt that there would be any problem using either in a modern firearm in good condition/