5.56 build differences compared with .223

[Skeet Mcgee]

I posted this in newbie FAQ's but thought you long gun lads might be better suited for the job. I understand that firing 5.56 out of a .223 chamber is not a great idea. Can anyone tell me what the difference in the bolt/receiver/chamber of a 5.56 chambered rifle is that allows it to fire the 5.56 safely?

Quoted form my newbie post:

"I'm considering buying a Ruger American Ranch. It is chambered in 5.56/.223 while the other models of american rifles are chambered in .223 only. Does this mean the Ranch's chamber or action is beefier or somehow stronger to accommodate the higher pressure 5.56 round? I was under the impression that all Ruger American short actions were the same...

Any info is appreciated. Thanks."

 

[justinb1981]

The 5.56 has a slightly thicker case wall resulting in a slightly smaller volume and higher pressure. For safety's sake only shoot what's stamped on the gun

 

[tekarra]

The 5.56 also has a longer leade than the .223. Common wisdom is to shoot .223 in a 5.56 chamber but not vice versa. My choice is to use a rifle chambered in .223 Wylde. Other than AR15 rifles, I do not know who chambers the .223 Wylde.

 

[Hitzy]

Chamber dimensions are slightly different, that's the only physical difference in a rifle. Nothing is beefed up, longer throat and slightly looser tolerance for a 5.56 chamber.
http://www.ar15barrels.com/data/headspace.pdf

 

[weasel1]

To confuse things more, some rifle are marked as 223 when they are in fact 5.56.

 

[DT741]

To confuse things more, some rifle are marked as 223 when they are in fact 5.56.

I remember reading about it, apparently it would be an export thing. I guess its easier to export a rifle in 223 than the evil 5.56

 

[Sqr]

I posted this in newbie FAQ's but thought you long gun lads might be better suited for the job. I understand that firing 5.56 out of a .223 chamber is not a great idea. Can anyone tell me what the difference in the bolt/receiver/chamber of a 5.56 chambered rifle is that allows it to fire the 5.56 safely?

Quoted form my newbie post:

"I'm considering buying a Ruger American Ranch. It is chambered in 5.56/.223 while the other models of american rifles are chambered in .223 only. Does this mean the Ranch's chamber or action is beefier or somehow stronger to accommodate the higher pressure 5.56 round? I was under the impression that all Ruger American short actions were the same...

Any info is appreciated. Thanks."

Do not worry about it as its a non issue.

 

[Skeet Mcgee]

Chamber dimensions are slightly different, that's the only physical difference in a rifle. Nothing is beefed up, longer throat and slightly looser tolerance for a 5.56 chamber.
http://www.ar15barrels.com/data/headspace.pdf

Thanks all. Thai's exactly what I wanted to know.

Hitzy, your comment about looser tolerances has me thinking... would then a .223 chamber have more accuracy potential than a 5.56??

 

[Boomer]

Thanks all. Thai's exactly what I wanted to know.

Hitzy, your comment about looser tolerances has me thinking... would then a .223 chamber have more accuracy potential than a 5.56??

Not if you load your ammo to match the 5.56 chamber. If you typically seat out the bullet to contact or have a short jump to the lands, in a cartridge case that has already been fired in a 5.56 chamber, you are essentially loading a 5.56 cartridge for precision, regardless of the cartridge headstamp. Any difference in precision between the 5.56 and the .223 comes down to the quality of the barrels, the machining, and the bedding of each individual rifle, rather than there being any inherent accuracy advantage of SAMMI or CIP chamber dimensions.

 

[Hitzy]

PMC at least has a warning on their green tip 556....

 

[SteelCap]

As a side, if the barrel says 223 wylde...you can shoot both.