5.56 in .223?


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xstuntman
September 1, 2009, 12:28 AM
I'm thinking of getting my first AR from DPMS and I heard from someone at work that 5.56 will not work in a .223 chamber. Truth?

Thanks, Mike

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jpwilly
September 1, 2009, 01:41 AM
Shouldn't do it...223 in 5.56 is okay not the other way around.

hadmanysons
September 1, 2009, 01:44 AM
As I've generally understood it, 5.56 is not a good idea in a .223 chamber. Different pressure and different dimensions something something. But .223 in a 5.56 chamber is ok. Anyway...

http://en.wikipedia.org/wiki/5.56x45mm_NATO

http://ammo.ar15.com/ammo/

http://www.ar15armory.com/forums/556-223-Ammunition-Ch-t22582.html

Frankl03
September 1, 2009, 01:46 AM
Most ARs are chambered in 556. You can shoot 223 in a rifle chambered in 556.

Big44mag
September 1, 2009, 10:34 AM
You can also use 5.56 in a 223 Wylde chamber which a few manufacturers use like White Oak, Rock River, Rainier, JP to name a few.

BornAgainBullseye
September 1, 2009, 10:53 AM
once again to all you so called internet experts.... If either round. is so different in pressure.... then wait for it......... WHY does both have the same muzzle velocity given the same weight bullet (55grain vs 55grain) ???? if either operated in a different pressure range then velocity would be up or down... We or anyone who has a micrometer has already established that the external dementions of 5.56 and .223 rem are external matches. The only difference is thickness of brass in some cases and a crimped primer which is NATO standard. The difference and only difference lies in the chamber. the nato chamber is a little long strictly for battlefield conditions and aiding in reliable extraction in very very cold or dirty weather. Once again My round count on my and my friends AR chambered in 5.56 is in the thousands yes plural. and we still hit MOA. We are reloading using a RCBS .223 remington small base die set. ZERO failures due to ammo. Only a few Pro Mag failures, but we solved that with a garbage can..... so now all you nay sayers bring the heat if you have your thong in a wad. Experience speaks for myself.

longdayjake
September 1, 2009, 11:08 AM
Okay, first of all they are saying that you shouldnt shoot 5.56 bullets out of a .223 chamber. You are shooting .223 reloads from a 5.56 chamber so your argument is moot.

briansmithwins
September 1, 2009, 11:10 AM
Speaking of 'internet experts'...

SAAMI lists 5.56 NATO in a .223 Remington chambered rifle as a unsafe combination.

You can read more about it here: http://www.saami.org/Unsafe_Combinations.cfm

BSW

Mr_Pale_Horse
September 1, 2009, 11:40 AM
SAAMI - Sporting Arms and Ammuntion Manufacturing Institute = 5 parts marketeer, 4.5 parts lawyer, .5 part technical anything

That link above contains 95% pure bunk, based solely on A) we want to sell ammo and can't compete against milsurp prices and B) the "we don't want to get sued" mentallity.

First of all, many of those proscribed combinations simply will not chamber in the first place.

Second, read and follow the manufacturer's recommendation on ammunition and not follow some third party industry lobby.

CZguy
September 1, 2009, 11:42 AM
Speaking of 'internet experts'...

SAAMI lists 5.56 NATO in a .223 Remington chambered rifle as a unsafe combination.

You can read more about it here: http://www.saami.org/Unsafe_Combinations.cfm

BSW

You beat me to it.

Sometimes people don't let physics get in the way of a good opinion. :D

Mr_Pale_Horse
September 1, 2009, 11:58 AM
The rest of the story:
In 1979, SAAMI cautioned shooters that 5.56mm military chambers and throats differ from 223 sporting chambers, and therefore military ball ammo may produce high chamber pressures in sporting rifles. At least one manufacturer, Ruger, harumphed that its 223 chambers would handle military 5.56mm with no problems. KW
Ken Warner, editor of Cartridges of the World, 6th Edition, 1989, by Frank C. Barnes

sporting emphasis added by me

File this one under "old wives tale."

Dr. Tad Hussein Winslow
September 1, 2009, 12:05 PM
In 1979, SAAMI cautioned shooters that 5.56mm military chambers and throats differ from 223 sporting chambers, and therefore military ball ammo may produce high chamber pressures in sporting rifles.

An AR with a match .223 chamber IS a "sporting rifle".

Mr_Pale_Horse
September 1, 2009, 12:14 PM
Sporting was emphasized by me to denote they want you to buy pricey sporting or match ammo, rather than cheap ball.

A match ANYTHING will prefer custom, fire formed, neck turned, neck sized, handloaded, precision made rounds, to which every SAAMI manufacturer (other than reloading suppliers) says "Nay".

taliv
September 1, 2009, 12:21 PM
once again to all you so called internet experts.... If either round. is so different in pressure.... then wait for it......... WHY does both have the same muzzle velocity given the same weight bullet (55grain vs 55grain) ???? if either operated in a different pressure range then velocity would be up or down...

as a reloader, perhaps you can explain why published maximum pressures vary by powder for the same bullet.

hmm....

JonB
September 1, 2009, 12:22 PM
If I recall correctly, SAAMI measures pressure differently than military. So the pressure argument isn't necessarily an apples to apples comparison if your measuement systems are different.

Anybody know the military spec for velocity/pressure for 5.56mm 55gr pills?

Tim the student
September 1, 2009, 12:22 PM
once again to all you so called internet experts....

Pot, meet Kettle. Kettle, this is pot.

Once again My round count on my and my friends AR chambered in 5.56

Um, so you are shooting .223 in a 5.56 chamber? Well, Mr. Pot, that is what is considered as safe.

Thanks for verifying.

taliv
September 1, 2009, 12:23 PM
oh, and in my experience with the chrono, actual m193 shoots way faster than your run of the mill 55g 223rem like winchester white box or UMC

Uncle Mike
September 1, 2009, 12:34 PM
military ball ammo may in sporting rifles.

5.56mm military chambers and throats differ from 223 sporting chambers,

Obviously there may have been, in isolated and unique circumstances, failures of such...

This would lead a agency such as SAMMI to issue precautionary or even mandatory directives concerning the matter. Cover your a$$, is a policy that extends to every governing body...

As any of us who reload, test and monkey around with...even being drunk monkeys, various ammunition we see that only in very limited cases 5.56 being loaded to grossly higher pressures than good .223.

I was told by an old timer...WOW, I have some stones to be talking, "old timer"... that
.223 was indeed not as aggressive as 5.56 in the pressure category, reason being the military is concerned with reliable function...after all the AR/M-16 platform was designed as an 'use and toss' system.

I do not adhere to that theorem!

briansmithwins
September 1, 2009, 12:53 PM
Second, read and follow the manufacturer's recommendation on ammunition and not follow some third party industry lobby.

Got any citations of manufacturer's saying that 5.56 NATO is safe in .223 Rem chambered weapons?

Links?

BSW

CMP
September 1, 2009, 01:03 PM
Well xstuntman you can be on the safe side and get it in 5.56 to begin with, my DPMS is in 5.56.

Mr_Pale_Horse
September 1, 2009, 01:10 PM
Ruger:

The Mini-14 manual states that the .223 Remington(5.56mm) or 6.8mm Remington SPC cartridge models are:

designed to use either standardized U.S. military, or factory loaded sporting cartirdges

Conversely, the manual specificly states:

The Target Model uses .223 Remington cartridges only.

Their emphasis, not mine this time.

So, put away the broad brush. Read your owners manual. Not all 223 models can, but not all cannot use 5.56 mm Ball.

Onmilo
September 1, 2009, 01:14 PM
The word is all new non match grade DPMS rifles now come with 5.56 NATO chamber dimensions.
Older DPMS rifles should be headspace checked for NATO chamber, many or most will display chamber closer to commercial .223 Chamber.

Bolt action sporting rifles should never be fired with NATO dimension cartridges but any rifle with a non chrome lined chamber can be easily reamed to 5.56 NATO dimensions which will aloow commercial or NATO dimension cartridges to be fired safely.

The gunsmith reaming any chamber should also clearly mark the chamber 5.56 NATO to avoid confusion.

Neo-Luddite
September 1, 2009, 01:16 PM
Get it in writing from the maker of the specific weapon you are buying.

As said, with Ruger being a GREAT example; most Mini's are marked .223 but WILL handle 5.56 NATO. THEY SAY SO.

Call the company--get it IN WRITING.

CoRoMo
September 1, 2009, 01:36 PM
Anyone ever heard of a single instance where 5.56 ammo caused a problem in a .223 gun?

Anyone believe litigious apprehension was not a factor in SAAMI's position?

JonB
September 1, 2009, 02:19 PM
Never heard/read of an instance where 5.56 caused an issue in a .223. I would have thought that such a story (if exists) would have certainly popped up here or over at arfcom.

May have been a factor years and years ago, but does anyone believe that gun makers don't factor in 5.56 pressure when designing a .223 gun?

Mr_Pale_Horse
September 1, 2009, 02:19 PM
I looked at the drawings for 223 Remington and 5.56mm NATO cartridges (not chambers). The only difference is that the 223 calls for 0 radius of curvature at the neck/shoulder and shoulder/wall transitions, whereas the 5.56mm has a 2.54 mm radius and a 0.64 mm radius, respectively.

Nick5182
September 1, 2009, 02:34 PM
Since we're on the subject...I'm currently building an AR-15 and haven't chosen an upper yet. I'm using a DPMS lower with a DPMS lower parts kit, and would like to keep everything DPMS. However, all of the DPMS uppers I've looked at online say .223 Remington chamber. Given what "should" and "should not" be used as per SAAMI and NATO specs, then these upper assemblies are .223 and should not use 5.56 ammo, right?

Acera
September 1, 2009, 02:38 PM
Neither are loaded to max pressures.

Even the strongest 5.56 is typically loaded by the lawsuit paranoid brand name manufacturers to less than accepted maximums of the .223.

CoRoMo
September 1, 2009, 02:39 PM
does anyone believe that gun makers don't factor in 5.56 pressure when designing a .223 gun?

I think they do. I've fired 5.56 military through a Rem 700 and there wasn't the slightest indication of the tell-tale signs of excessive pressures.

JonB
September 1, 2009, 02:43 PM
The 5.56 mm NATO and .223 Remington cartridges and chamberings are similar but not identical. Military cases are generally made from thicker brass than commercial cases; this reduces the powder capacity (an important consideration for handloaders[8]), and the NATO specification allows a higher chamber pressure. NATO EPVAT test barrels made for 5.56 mm 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 MPa (20,000 psi) difference in pressure measurements. This means the NATO EPVAT maximum service pressure of 430 MPa (62,366 psi) for 5.56 mm NATO, is reduced by SAAMI to 379.21 MPa (55,000 psi) for .223 Remington.[9] 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 5.56 mm NATO.
Source (http://en.wikipedia.org/wiki/5.56x45mm_NATO)

Acera
September 1, 2009, 02:46 PM
xstuntman try a search on this. This subject is almost as well covered as the 9mm vs. .45 debate.

Hopefully a moderator will make a sticky out of one of these discussions for the new people.

taliv
September 1, 2009, 02:47 PM
i'd encourage some of you to do a little research online into ned christiansen's chamber reamer.

it's a popular tool at carbine classes. all too common scenario is ammo popping primers in 5.56nato marked barrels. use the chamber reamer, and out comes this metal. (implying the chamber was 'tight') magically, the primer popping stops.

it really doesn't take a lot to increase the pressure in there.

Mr_Pale_Horse
September 1, 2009, 03:00 PM
A popped or raised primer is less an indication of pressure than of a sticky or rough chamber. Flattened primers, blown primers, difficult extraction, incipient head separation lines are all indications of high chamber pressure.

CMP
September 1, 2009, 03:02 PM
Since we're on the subject...I'm currently building an AR-15 and haven't chosen an upper yet. I'm using a DPMS lower with a DPMS lower parts kit, and would like to keep everything DPMS. However, all of the DPMS uppers I've looked at online say .223 Remington chamber. Given what "should" and "should not" be used as per SAAMI and NATO specs, then these upper assemblies are .223 and should not use 5.56 ammo, right?

Nick5182 when I ordered my DPMS upper from CTD when they where priced good it said .223 when I got it, it said 5.56 on the barrel.

CoRoMo
September 1, 2009, 03:21 PM
the DPMS uppers I've looked at online say .223 Remington chamber. Given what "should" and "should not" be used as per SAAMI and NATO specs, then these upper assemblies are .223 and should not use 5.56 ammo, right?

This guy (http://www.thehighroad.org/showthread.php?t=413532) was told, by DPMS, that his gun would survive the 5.56 ammo.

Mr_Pale_Horse
September 1, 2009, 03:55 PM
Winchester's Reasoning:

News and Press Releases

.223 Rem VS 5.56mm

Paul Nowak
5/4/2001
.223 Rem VS 5.56mm

There are a lot of questions about these two cartridges. Many people think they are identical - merely different designations for commercial and military. The truth is that, although somewhat similar, they are not the same and you should know the differences before buying either cartridge.


The cartridge casings for both calibers have basically the same length and exterior dimensions.
The 5.56 round, loaded to Military Specification, typically has higher velocity and chamber pressure than the .223 Rem.
The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader.
The 5.56mm and .223 Rem chambers are nearly identical. The difference is in the "Leade". Leade is defined as the portion of the barrel directly in front of the chamber where the rifling has been conically removed to allow room for the seated bullet. It is also more commonly known as the throat. Leade in a .223 Rem chamber is usually .085". In a 5.56mm chamber the leade is typically .162", or almost twice as much as in the 223 Rem chamber.
You can fire .223 Rem cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity over firing the .223 round in the chamber with the shorter leade it was designed for.
Problems may occur when firing the higher-pressure 5.56mm cartridge in a .223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads and gun functioning issues.
The 5.56mm military cartridge fired in a .223 Rem chamber is considered by SAAMI (Small Arm and Ammunition Manufacturers Institute) to be an unsafe ammunition combination.


Before buying either of these two types of ammunition, always check your gun to find what caliber it is chambered for, then buy the appropriate ammunition. Most 5.56mm rounds made have full metal jacket bullets. Performance bullets - soft points, hollow points, Ballistic Silvertips, etc. - are loaded in .223 Rem cartridges. Firing a .223 Rem cartridge in a 5.56mm-chambered gun is safe and merely gives you slightly reduced velocity and accuracy. However we do not recommend, nor does SAAMI recommend, firing a 5.56mm cartridge in a gun chambered for the .223 Rem as the shorter leade can cause pressure-related problems.

Winchester Law Enforcement Ammunition

East Alton Illinois


My emphasis added.

Maverick223
September 1, 2009, 05:05 PM
BSW got it right...and Taliv is absolutely right about the different pressures (and velocity) between .223Rem and 5.56NATO...if they were the exact same cartridge then it would only have one name. Many cartridges are similar (lets not get into which ones) but there is always a difference (with exception of wildcats being renamed when they become accepted factory loads). :)

Tacbandit
September 1, 2009, 09:48 PM
Xstuntman...You've read a lot of stuff in this thread you started...Regardless of what brand rifle you buy, remember this...shooting .223 ammo in a 5.56 upper is ok...shooting
5.56 in a .223 upper probably shouldn't be done...There are warnings about it...ask yourself why...??? There are pressure differences. Just because someone else does it and says it's ok, doesn't make it so...Be safe...not sorry...Just buy one that's rated for 5.56, and this whole thread will be a moot point...

kwelz
September 1, 2009, 09:51 PM
One thing that also causes a lot of confusion is that just because a barrel is marked 5.65, doesn't mean it is 5.56. Bushmaster chambers for instance are very tight normally. I have had a number of bad DPMS chambers personally as well.

Maverick223
September 1, 2009, 10:37 PM
One thing that also causes a lot of confusion is that just because a barrel is marked 5.65, doesn't mean it is 5.56.Yeah...but 5.65 ammo is so hard to come by now. :neener:

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