.223 vs 5.56

[jetrecbn1]

What's the difference? This might be in the wrong area, but wanted more to reply. I thought they were the same, now someone tells me I'm wrong. That's probably why my AR15 is jamming. Don't know.

[Don Gwinn]

I also thought they were the same thing. This'll probably get moved to Art of the Rifle as soon as a moderator bestirs himself. Now you've got me wondering.

[Dennis]

Ahem! Yes! Consider me bestirred, not beshaken.

As predicted, you're off to the Art of the Rifle!
Seriously, that's where the rifle experts are..

[Art Eatman]

Well, if you multiply 5.56mm X 0.03937 inches/mm you get...

The .223 Remington is the name for the military's 5.56 X whatever number of millimeters the case length is...

Same animal.

Same sort of thing happens with the .308 Winchester. Same as NATO's 7.62 X whatever. 51mm? Not to be confused with .308 Norma Magnum, or 7.62X39 AK round...Confused?

There is no set standard for cartridge nomenclature. For instance, what is commonly referred to as the "8mm Mauser" is also called the "8X57". You just learn as you go.

(I don't have a loading book handy to check some of the numbers...)

Regards, Art

[jetrecbn1]

That's what I thought. Went to GT stated the same thing but was refutted. Something about the neck angle. I knew I ain't that dummmm.

[dZ]

yep to aid in extraction 5.56 chamber is a tad looser than a .223 chamber

[MountainGun44]

THERE IS A DIFFERENCE!!!!!

If you have a rifle with a .223 barrel- especially if it is a "match" barrel- you may have problems with 5.56 ammo. Especially Winchester Q3131 5.56mm ammo. If you read the box you will find that it says .223 NOWHERE ON THE BOX OR ON THE AMMO. Typical symptoms of this problem include failure to extract, failure to fully cycle, failure to strip the next round into the chamber,double striping, etc. My Bushmaster shoots like a single shot with 5.56mm ammo. It jams almost every shot. The .223 chamber is not the exact dimensions of a 5.56mm mil-spec chamber. It is a bit tighter. My Mini-14 will shoot 5.56mm ammo all day. My Bushmaster with a Wilson barrel will not function reliably. A 5.56mm chambered rifle will typically not shoot as tight a group as a match barrelled .223 rifle.

Some rifles do not have this problem, but many do.

MANY, MANY PEOPLE WILL SAY THEY ARE THE SAME BECAUSE THEY DON'T KNOW WHAT THEY ARE TALKING ABOUT.

THIS IS NOT A MAGAZINE PROBLEM. IT IS NOT A CLEANING PROBLEM. IT IS AN AMMO PROBLEM.

TRY A SEARCH FOR "Q3131" ON AR15.COM, THEN FOLLOW THE TRAIL. NEXT TIME SOMEONE ARGUES WITH YOU ABOUT THIS, MAKE A BET.


try this
http://forums.ar15.com/Forum14/HTML/001085.html

[This message has been edited by MountainGun44 (edited August 01, 2000).]

[dbrowne1]

There is a difference. MountainGun44 summed it up well. If you have a 5.56 chamber (for ARs that means a preban Colt, Bushmaster other than the DCM match gun, or an Armalite)then you may use 5.56 or .223. Any other barrel is probably a .223 and 5.56 may not work properly.

[Chris Orndorff]

So, I'm reading that there IS a difference, although the difference is in chamber spec, not case spec. Anyone got the measurements?

[orsogato]

Interesting, I always thought they were the same round.

In My POST BAN colt match target rifle all i use is Lake City Mfcted US Military 5.56mm ammo. I have never had an extract problem. My lower receiver is marked .223

My Bushy; the lower receiver is marked 5.56mm-.223. Never had a problem with that rifle either feeding military Ammo. Both Lake City and that Berdan primed South African Battle Pack stuff.

DONT USE Steel Cased ammo. Maybe that is the problem. I'd stay away from stuff like Wolf, TRW etc.

[Banzai]

THERE IS A DIFFERENCE!!!!!!!!!!!!!!!!


OK, here we go again. ACCORDING TO SAAMI (THE PEOPLE WHO SHOULD KNOW) THERE IS NO DIMENSIONAL DIFFERENCE IN .223 AND 5.56mm CARTRIDGES. THE DIFFERENCE IS IN PRESSURE LEVELS OF THE LOADED CARTRIDGES.
.223 is lower pressure (about 52,000 CUP) and 5.56mm is designated as higher pressure. SAAMI has long stood by their recommendation that 5.56 not be used in rifles labeled as .223 because of the risk of overpressure. It may never happen in your gun, but it's like using 38+P in a revolver designated as 38 only.
MountainGun44 also hit upon the differences in chambers. THIS IS ALSO NOT A SAAMI REGULATED DIMENSION. Military rifles and some others use a SLIGHTLY larger chamber to facilitate feeding/extraction, especially under sustained fire(heat build up) and in messy conditions (duh-the battlefield!) Remember, the first and most important thing about a combat arm is RELIABILITY, thus, the larger chamber.
It's really usually only a matter of running a finishing reamer through the chamber after the rough reamer a few more times than usual to get a 5.56 chamber instead of a .223 chamber. THEY ARE THE SAME TOOLS. HOWEVER, some manufacturers use finishing reamers that are slightly larger, thus facilitating faster prodiction and lower tool wear.
I just had a CLE AR15 upper made, and I called them with this specific question. Above is what they told me, which mirrors what my local gunsmith buddy (45 years as a tool and die maker/gunsmith) and the SAAMI web site.

THERE IS A DIFFERENCE!!!!!!!!!!!!!!!

Tom

------------------
A "Miss" is the ultimate overpenetration!
You can never be too rich, too skinny, or too well armed!
Wake up and realize that you have the moral imperative of action..!!!

[4V50 Gary]

Concur with MountainGun & Banzai on the difference. Same applies to .308 Winchester and 7.62 mm Nato.

[Chris Orndorff]

Still seeing some ambiguity here re the "difference". Looks like they are identical cartridges (dimensionally) but chambers are slightly different.

[dZ]

The Mil SPec on AR15 M4 head space is:
3.4.1 Head Space The head space shall not be less than
1.4646 inches nor more than 1.4706 inches when measured to the
.330 inch datum diameter on the first sholder of the chamber.

here is the spec on
CARTRIDGE, 5.56MM, BALL, M193
Type Classification:
STD - AMCTC 5143.
Use:
Rifles, 5.56mm, M16 and M16A1. The cartridge is
intended for use against personnel and unarmored
targets.
Description:
BALL Cartridge. The cartridge is identified by a plain
bullet tip.
Tabulated Data:
DODAC...............................1305-A066
UNO serial number ............0012
UNO proper shipping
name ...............................Cartridges for
weapons, inert pro-jectile
Weight ................................182 gr
Length.................................2.26 in. (57.4 mm)
Tracer .................................NA
Primer.................................Percussion
Fuze....................................NA
Explosive:
Type ...............................NA
Weight ............................NA
Incendiary:
Type - ..............................NA
Weight ............................. NA
Propellant:
Type ...............................WC 844 or
CMR 170
Weight .............................28.5 or 26.5 gr
Projectile:
Weight .............................56 gr
Performance:
Chamber pressure...............52,000 psi
Velocity ..............................3250 fps, 15 ft from
muzzle
Shipping and Storage Data:
Quantity-distance class/
SCG ................................1.4S
Storage code ......................Class V

>>>>>>>>>>>>>>>>>>>>>>>>>>>

CARTRIDGE, 5.56MM, BALL, M855
Type Classification:
STD - MSR 05826003.
Use:
Machine Gun, 5.56mm, M249E1; and Rifle, 5.56mm,
M16A2. The cartridge is intended for use against
personnel and unarmored targets.
Description:
BALL Cartridge. The cartridge is identified by a green
bullet tip.
Tabulated Data:
DODAC...............................1305-A059
UNO serial number .............0012
UNO proper shipping
name...................................Cartridges for
weapons, inert pro-jectile
Weight ................................190 gr
Length.................................2.26 in. (57.4 mm)
Tracer .................................NA
Primer.................................Percussion
Fuze ...................................NA
Explosive:
Type ................................NA
Weight .............................NA
Incendiary:
Type ...............................NA
Weight .............................NA
Propellant:
Type ...............................WC 844
Weight ............................26.1 gr
Projectile:
Weight .............................62 gr
Performance:
Chamber pressure ..............55,000 psi
Velocity ..............................3025 fps, 78 ft from
muzzle
Shipping and Storage Data:
Quantity-distance class/
SCG.................................1.4S
Storage code ......................Class V
DOT shipping class .............C
DOT designation .................SMALL ARMS
AMMUNITION
Drawing number .................9342862
References:
DARCOM 700-3-2
TM 9-1300-206
TM 9-1305-201-20&P

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
proofing is done with
CARTRIDGE, 5.56MM, HIGH PRESSURE TEST, M197
Type Classification:
STD - AMCTC 4484.
Use:
Rifles, 5.56mm, M16 and M16A1. The cartridge is
used to proof test weapons during manufacture, test, or
repair.
Description:
HIGH PRESSURE TEST Cartridge. The cartridge is
identified by a stannic-stained (silvered) or nickel-plated
cartridge case.
Function:
The cartridge is loaded with a special propellant to
produce pressures substantially in excess of the service
round.
Tabulated Data:
DODAC...............................1305-A070
UNO serial number .............0012
UNO proper shipping
name ..................................Cartridges for
weapons, inert pro-jectile
Weight ...............................174 gr
Length................................. 2.26 in. (57.4 mm)
Tracer .................................NA
Primer.................................Percussion
Fuze....................................NA
Explosive:
Type ................................NA
Weight ............................NA
Incendiary:
Type ................................NA
Weight .............................NA
Propellant:
Type ...............................SR 7641
Weight-............................16.7 gr
Projectile:
Weight .............................56 gr
Performance:
Chamber pressure...............70,000 psi
Velocity ..............................NA
Shipping and Storage Data:
Quantity-distance class/
SCG ................................1.4S
Storage code.......................Class V

[dZ]

TECHNICAL DATA SHEET http://www.saami.org/unsafe3.htm
UNSAFE ARMS AND AMMUNITION COMBINATIONS

Ammunition used in a firearm must be the same caliber or gauge as that marked on the firearm by
its manufacturer. If the firearm is not marked as to the caliber or gauge, or if it appears that the
original marking has been overprinted or changed, it is the responsibility of the gun user to have a
qualified person determine what cartridge or shell can be safely used in the firearm.

The firing of a cartridge or shell other than that for which the firearm is chambered can result in the
cartridge or shell rupturing and releasing high pressure gas that can damage or destroy the firearm
and kill or seriously injure the shooter and persons nearby.

There are countless combinations of specific cartridges and firearms which are unsafe. Many of
these unsafe combinations are recognizable because of specific differences between the similar
chamber and cartridge dimensions. It is not possible to list every unsafe combination; therefore, in
the interest of safety, use only the cartridge (or shell) designated by the firearm or ammunition
manufacturer for use in a specific firearm. The cartridge caliber or shotshell gauge must be marked
on the firearm frame, receiver or barrel by its manufacturer.

The practice of rechambering firearms is not guided by industry standards. It is possible that a
firearm which has been rechambered may not be rechambered properly or the rechambered caliber
may not be marked on the firearm. The firearm user is responsible to find out from a qualified
person the cartridge caliber or shell gauge for which the firearm has been rechambered.

CENTERFIRE RIFLE
In Rifle Chambered For
223 Remington
Do Not Use These Cartridges
5.56mm Military

[dZ]

here is some data on .308 vs 7.62 x 51
http://www.fulton-armory.com/308.htm

[RikWriter]

Okay, so the deal is, you can use 223 in 5.56x23 marked guns then, but not the opposite, correct? (I suspect this is correct since I have done so for years...all the ARs I have owned have been 5.56mm)

[Art Eatman]

RikWriter: From what's posted above, the answer seems to be, "Technically, yes."

SFAIK, folks been shooting GI stuff in civilian rifles, and civilian stuff in GI rifles, since the AR-16/M16 first came out.

My question would be whether anybody has SEEN a blowup from "wrong ammo"? I have never heard of one, for whatever that's worth...

I've run a lot of GI ammo and reloads of GI brass through three Mini-14s, two AR-15s and one M-16, and two bolt actions, with nary a problem of any sort. Dangifino.

, Art

[Prof]

This question has come up before and I asked about it once myself. I specifically asked if I could shoot 5.56 military surplus ammo through my Ruger M77 Mk II bolt-action .223 rifle. The consensus was split so I called Ruger and the Technical Division people told me that it was safe to shoot any milsurp 5.56 ammo through the .223 Ruger (!). So, I sent them a letter asking the same question. I feel that if I get the same answer in writing then I will go ahead and use the 5.56. This stuff is confusing as h*ll!

[Lavan]

I got such a deal on a BUNCH of military 5.56 that I went out and bought a mini-14 to shoot it all up. So far have shot 2-3000 rds with no ill effect. Still have thousands left so it BETTER work.

[Kevinw]

One thing to point out. Ruger actions are made very strong. Technically they are the strongest of the main Manufactuers. Colt, Sig, Remington, etc, etc. so I don't hink using slightly higher pressure rounds would hurt the gun. Now if you had some no name $150.00 Rifle I might tell you differently.

[dZ]

here is the skinny from my favorite LTC:
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>There are no "cartridge" headspace specs. There are, however, weapons
headspace specs. There is, for example, no 5.56mm NATO headspace spec.
All depends on the weapon in question. SAAMI has adopted a recommendation
for bolt action rifles. Using this in other firearms is a mistake.

Semiautomatic and automatic weapons have larger headspace specifications to
insure proper functioning. There are separate headspace specification for
the M14 rifle and the various 7.62mm NATO machineguns for example, just
like there's a different spec for the M16A2 and M249 SAW, both of which are
5.56mm.

I get really tired of the old women in the world worrying about "excessive
headspace." Unless one uses a grinder there's no way you can get
"dangerous headspace." You'll wear out the barrel first.

There are no safety or any other issues firing .308 ammunition in the M14 and other 7.62mm NATO weapons provided the weapons meet weapon headspace
requirements. Same for .223 in the M16A2 or SAW.

Nit picking and quibbling aside 7.62mm NATO and .308 Winchester are
functionally identical meaning you can fire either cartridge with impunity
as needed. Same for 5.56mm NATO and .223 Remington.

Military cartridges normally have thicker cases making them smaller on the
inside than commercial cases. Outside they're the same within tolerances.

Anyone who tells you that 7.62mm and .308 have different "headspaces"
hasn't a clue what headspace's function is. Same same for 5.56mm and .223.
Weapons have headspaces, not cartridges.

For reliable operation the AR15 should use the M16A2 headspace. Notice
there's no mention of caliber here.

- -- Chuck[/quote]

[Art Eatman]

dZ: A couple of minor quibbles on the headspace thing: Too tight a chamber, the bolt won't close or lock into battery. Too much headspace in the chamber, and the case might seat just enough forward that it's possible for the primer to be blown out, making life exciting for the shooter.

The latter case is of significance only on "put together" guns--typically older military bolt actions--where one has no idea of the history. For currently-shot rifles, it's almost unheard of...

No biggie, Art

[MountainGun44]

The whole thing is not very complicated. If you have a .223 barrel, it probably has a tighter chamber. It may have trouble shooting 5.56mm ammo reliably. It may not. My Bushmaster has a big problem with 5.56mm ammo. My Mini-14 does not. If you want to increase the chance that your rifle will function reliably with anything you put in it-buy a 5.56mm barrel. It may not have the "match accuracy" of a .223 barrel, but it will be more likely to happily digest your ammo without faillure in adverse conditions. A bolt action rifle is a different animal. The fact that is safe to fire 5.56mm in a Ruger M77 really has nothing to do with the question.

If there was no difference, why would SAAMI say there is a difference?

[Glamdring]

What it boils down to is that the 5.56x45mm and 223 are the same cartridge. But when it says 5.56 the cartridge [or gun] is not held to SAAMI tolerances...the 5.56 is held to what NATO specs? You can run into the smae problem with 9x19mm ammo or 45 acp.

If you think that is the problem with your AR take it in and have them slip go/no go gages in or take a caliper to your rounds before you shoot them and check OAL.

If long (measured) rounds give you problems then you have ID the problem. You might also look at bullet shape.