5.56 vs. .223 - AR15.COM

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Posted: 1/6/2006 8:09:37 AM EDT

I have a guy at work that used to work for a major ammunition company. He is convinced 5.56 is loaded the same as .223 SAAMI.

Posted: 1/6/2006 8:11:46 AM EDT

[#1]

If he wont take any of those reasorces.

I doubt any thing will change his mind, just let him live in his little fantisy land

Posted: 1/6/2006 8:12:25 AM EDT

[#2]

That's not enough?

AND he used to work at a major ammo company...?

There may not be enough to convince him.

Try the Maryland AR site- they've got some great info there too. I don't know the URL offhand.

Posted: 1/6/2006 8:55:34 AM EDT

[#3]

He works for a major ammo company? He/they shoiuld have more access to any info the we do, since they are doing this for a living.

Posted: 1/6/2006 8:59:00 AM EDT

[#4]

Everything you ever wanted to know about .223 and 5.56

ETA
Oops, missed the "besides the Ammo-Oracle" part.

Posted: 1/6/2006 9:08:08 AM EDT

[#5]

This guy is a moron. Don't try to reason with him. His head might explode.

Posted: 1/6/2006 9:10:44 AM EDT

[#6]

Quoted:
He works for a major ammo company? He/they shoiuld have more access to any info the we do, since they are doing this for a living.

I wonder if he was a driver or something...

If he doesn't know the difference between SAAMI spec and NATO spec by now...

Posted: 1/6/2006 9:12:15 AM EDT

[#7]

He must be confused.

Posted: 1/6/2006 9:25:57 AM EDT

[#8]

Well, IF he did work for a major ammunition manufacturer, he should be aware of the Small Arms Ammunition and Manufacturing Institute, SAMMI.

He and/or you can get the official technical publication on .223 and 5.56. Better yet, direct his attention to www.saami.org/unsafe3.htm------ask him why, if .223 and 5.56 are the same, SAMMI recommends (under the Centerfire Rifle Section) that firearms chambered for .223 NOT use 5.56 Military ammunition?

(Edited to correct link)

Posted: 1/6/2006 9:31:32 AM EDT

[#9]

From SAAMI UNSAFE ARMS AND AMMUNITION COMBINATIONS list

In Firearms Chambered For Do Not Use These Cartridges
223 Remington 5.56mm Military

222 Remington

30 Carbine

www.saami.org/unsafe3.htm

ETA
Damn I'm slow

Posted: 1/6/2006 9:57:18 AM EDT

[#10]

He says it has nothing to do with the loading. He says the higher pressures come from a different throat cut and the military bullet having a tangent ogive rather than a secant ogive.

Posted: 1/9/2006 6:19:34 PM EDT

[#11]

Quoted:
He says it has nothing to do with the loading. He says the higher pressures come from a different throat cut and the military bullet having a tangent ogive rather than a secant ogive.

Anyone have a comment about this?

Posted: 1/9/2006 6:29:05 PM EDT

[#12]

Let me be the first to say...

Thank god for google

Secant vs. Tangent Ogive noses

"There are two basic types of ogival nose shapes: the tangent ogive and the secant ogive. A tangent ogive has an arc which meets the body contour smoothly, thereby creating no break in line where the ogive joins the cylindrical body. In other words, the center of rotation of the arc is in the plane of the base of the nose. If the center of rotation of the arc is aft of the plane of the base of the nose, you’ve got a secant ogive. Simple, no?"

now if someone could make sense of how that effects chamber pressures, I would be happier...

EPOCH

Posted: 1/9/2006 7:00:16 PM EDT

[#13]

I've posted this probably 5 or 6 times - I think it's a pretty explanation.

www.winchester.com/lawenforcement/news/newsview.aspx?storyid=11

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

Posted: 1/9/2006 7:02:27 PM EDT

[#14]

Sounds like the moron that works at my local Sportsman Warehouse.

I always ask if they have any 5.56mm Q3131a in the back and he says you mean .223

.

What a tard.

Posted: 1/9/2006 7:03:09 PM EDT

[#15]

Quoted:
I've posted this probably 5 or 6 times - I think it's a pretty explanation.

www.winchester.com/lawenforcement/news/newsview.aspx?storyid=11

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

nice explanantion

Posted: 1/9/2006 8:33:26 PM EDT

[#16]

A tangent ogive will give higher chamber pressures because the space inbetween the chamber and bullet is smaller.

Posted: 1/9/2006 8:36:29 PM EDT

[#17]

Quoted:
I've posted this probably 5 or 6 times - I think it's a pretty explanation.

www.winchester.com/lawenforcement/news/newsview.aspx?storyid=11

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

This doesn't explain why the chamber pressure is more in 5.56.

Could be many things:
Loaded with more powder?
Bullet ogive?
Powder burn rate?

Posted: 1/9/2006 8:43:54 PM EDT

[#18]

I have only shot 5.56mm in my old mini-14...never an issue.

What guns is it an issue in? The only 223 guns would be a mini-14 and some bolt guns. nearly all AR's are 556 as are 556 AK's. What else is there?

Posted: 1/9/2006 8:44:34 PM EDT

[#19]

Quoted:
This doesn't explain why the chamber pressure is more in 5.56.

Could be many things:
Loaded with more powder?
Powder burn rate?

Ding ding ding.

Posted: 1/9/2006 8:53:32 PM EDT

[#20]

I don't know about this tangent vs secant ogive thing ... but I can't wait to see those who do hash it out in this thread!

Posted: 1/9/2006 9:12:09 PM EDT

[#21]

There is a ton of .223 ammo that is loaded with bullets identical to 5.56 M193 bullets. For example, IMI makes both .223 and 5.56 loads using the exact same projectiles. Yet, the 5.56 loads exhibit higher pressure and higher muzzle velocity from the same rifle compared to the .223 loads.

What does that tell you?

-Troy

Posted: 1/9/2006 9:27:22 PM EDT

[#22]

That is what I tried to tell him.

Posted: 1/10/2006 2:46:46 AM EDT

[#23]

Quoted:
...I think it's a pretty explanation.

I shouldn't post when I'm tired.

That should read "I think it's a pretty good explanation"

Posted: 1/10/2006 8:22:03 AM EDT

[#24]

Quoted:
Quoted:
...I think it's a pretty explanation.

I shouldn't post when I'm tired.

That should read "I think it's a pretty good explanation"

I thought you thought it was bee-yootiful.

Posted: 1/10/2006 9:11:54 AM EDT

[#25]

Quoted:
I don't know about this tangent vs secant ogive thing ... but I can't wait to see those who do hash it out in this thread!

The difference is the rate that the ogive approches the point where the bullet meets the bore.

Simply, if you look at the space just before where the bullet meets the bore, the secant ogive has more space then the tangent. This means that the air in the barrel is compressed faster by the tangent and resaults in more pressure behind the bullet. Though I thnk this difference has a much lower effect on chamber pressures than the internal case difference that .223 vs. 5.56 have.

Posted: 1/10/2006 9:27:03 AM EDT

[#26]

I don't even try to explain it to people anymore. I just say ".223" and ".308" instead of 5.56 and 7.62 to make it simpler.

Posted: 1/10/2006 4:18:52 PM EDT

[#27]

Quoted:
Though I thnk this difference has a much lower effect on chamber pressures than the internal case difference that .223 vs. 5.56 have.

With the exception of Federal's terrible brass aside, there is NO difference in case dimensions, interior or exterior, between .223 and 5.56. The only differences are the pressure/velocity difference and that 5.56 ammo usually comes with "military" primers, meaning they are designed to be less sensitive, allowing them to be chambered repeatedly in guns with free-floating firing pins without going off unexpectedly.

Virtually all 5.56 bullets use tangent ogive noses anyway, so HIS explanation is wrong right from the beginning (though it IS true that a secant-ogive bullet may exhibit higher pressures than a tangent-ogive bullet of the same weight with the same charge in a short-throated rifle).

-Troy

Posted: 1/10/2006 4:27:20 PM EDT

[#28]

.

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