5.56 vs. 223 - AR15.COM

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Posted: 9/25/2005 1:07:15 PM EDT

If I understand correctly, a 5.56 chambered AR can take .223, but a .223 chamnbered AR canNOT take 5.56.

Is this correct?

Posted: 9/25/2005 1:11:49 PM EDT

[#1]

Ammo Oracle is your friend.

Seydou

Posted: 9/25/2005 1:28:57 PM EDT

[#2]

Quoted:
If I understand correctly, a 5.56 chambered AR can take .223, but a .223 chamnbered AR canNOT take 5.56.

Is this correct?

correct, 5.56 are usally loaded to higher pressures than .223

Posted: 9/25/2005 1:29:20 PM EDT

[#3]

Quoted:
If I understand correctly, a 5.56 chambered AR can take .223, but a .223 chamnbered AR canNOT take 5.56.

Is this correct?

Instead of sending you somewhere else for an answer yes you are correct. The ammo oracle is a great read though...highly recommended.

A wylde chamber can shoot 5.56 as well.

Posted: 9/25/2005 1:53:42 PM EDT

[#4]

I'll let you search, but go to the Winchester site - they have a great explanation that I have posted here in the past.

And yes, SAAMI (or is it SAMMI?) says don't shoot a 5.56 in a .223 chanber.

Posted: 9/25/2005 2:02:00 PM EDT

[#5]

All right, I felt bad about leaving you hanging. Here's the info I mentioned earlier.

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.

Posted: 9/25/2005 2:14:09 PM EDT

[#6]

Cool.

Thanks people.

Posted: 9/25/2005 2:18:52 PM EDT

[#7]

You betcha.

Posted: 9/25/2005 2:25:44 PM EDT

[#8]

Does anyone know if the Bushmaster 20" A2/A3 w/ bird cage flash suppressor rifle is chambered in 5.56?

Posted: 9/25/2005 2:27:48 PM EDT

[#9]

Quoted:
Does anyone know if the Bushmaster 20" A2/A3 w/ bird cage flash suppressor rifle is chambered in 5.56?

Bushmaster rifles use a 5.56 chamber.

Posted: 9/25/2005 3:05:17 PM EDT

[#10]

Quoted:
Quoted:
Does anyone know if the Bushmaster 20" A2/A3 w/ bird cage flash suppressor rifle is chambered in 5.56?

Bushmaster rifles use a 5.56 chamber.

And it should be stamped on the barrel.

Posted: 9/25/2005 6:08:50 PM EDT

[#11]

K, thanks. My Bushy is supposed to be in tomorrow (FIANALLY....FFL dealer ordered the wrong rifle the first time). I have a huge stash of .223 FMJ and some 5.56 tracers ready to try out.

Posted: 9/25/2005 7:50:12 PM EDT

[#12]

FooDog & dangerdan

to AR15.com.

[ARCHIVED THREAD] - 5.56 vs. 223

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