For those members NEW to AR's...

[OKC_Jim]

So if your not supposed to shoot a .223 through a 5.56 barrel, why are the producing them in such a manner? I was also reading up on this when I started looking into getting an AR finally a couple months ago. I had read the info about shooting a 5.56 out of a .223 chamber but did not see negative info about shooting .223 out of a 5.56 barrel.

Mike, I'm not sure I understand what you're asking so I apologize if the answer I give isn't to the question you asked.

First we understand that both 223 and 5.56 are both the same caliber and that case demensions are the same (I don't think you can even buy dies for 5.56 because they are the same as .223).

Basically there is a jump for the bullet from the case to the rifling. Generally the bullet shouldn't be in touch with the rifling when it is in the case. The 5.56 barrel is cut with a longer jump to the rifling than a .223 barrel. 5.56 bullets can extend out of the case further by spec than with the .223. Basically, my understanding is that, even though the case measurments are the same, you are allowed a longer over-all-lenght with the 5.56. Thus, both rounds will fit in a 5.56 chamber with out being in contact with the rifling. While both rounds might also fit in a .223 chamber, there is a chance that the 5.56 round will be in contact with the rifling. This can be a bad thing.

Also note that since the jump to the rifling is longer when using a 223 round in a 5.56 chamber, even though the round will work fine, you may notice a slight affect on accuracy.

That is my understanding. Hopefully I said everything at least somewhat correctly. I know it took me a lot of reading on various fora to try to understand what people were talking about.

Jim

 

[OKC_Jim]

You got that backwards. You can shoot .223 out of either chamber. You shouldn't shoot 5.56 out of a .223 chamber.

Yes I did get that backwards! Thanks for the catch. One of these days I'll learn not to do too many things at once.

Just to be clear for everybody else 5.56 can shoot either. 223 should only shoot 223. Then you get into other chambers such as the Wilde Chamber.

 

[Kinetics]

Are the differences between .223 spec chamber and a 5.56 NATO the same as the differences between .308 spec chamber and 7.62 NATO? Or do they have their own list of variances and nuances....?

7.62 and .308 is actually the opposite of 5.56/.223, .308 can over pressure 7.62 chambers, where as the 5.56 can over pressure .223 chambers.

Most makers use 5.56 barrels for everything now so you kinda of have to try to get a .223, but you should always check and know the difference for sure.

 

[cm_osu]

The Wylde chamber was designed to shoot both. At least one AR maker had/has a wylde chamber option though I don't remember which one.

Rock river does

 

[BIG_MIKE2005]

Yes I did get that backwards! Thanks for the catch. One of these days I'll learn not to do too many things at once.

Just to be clear for everybody else 5.56 can shoot either. 223 should only shoot 223. Then you get into other chambers such as the Wilde Chamber.

Thats what I was questioning cause I thought you had it backwards but the other member posted before you could reply & cleared it up for me.

 

[Dukester]

I've heard from several people who heard from their friends who are supposedly gunsmiths who say 5.56 through a .223 gun won't hurt a thing. It's simply amazing how many people suddenly know a gunsmith when they don't want to be wrong. It's also amazing how many jackasses are out there claiming to BE gunsmiths who are giving out bad/dangerous information to people that don't know better. I say it's always best to get your information from more than one source and everything I've ever read definitely agrees with this thread.

 

[OKC_Jim]

I've heard from several people who heard from their friends who are supposedly gunsmiths who say 5.56 through a .223 gun won't hurt a thing.

I have heard much the same thing. I say err on the side of caution.

 

[Dukester]

I have heard much the same thing. I say err on the side of caution.

It's not erring on the side of caution when the manufacturers themselves say its a bad idea and then go so far as to explain why. Most of those shadetree gunsmiths are hacks.

 

[OKC_Jim]

It's not erring on the side of caution when the manufacturers themselves say its a bad idea and then go so far as to explain why. Most of those shadetree gunsmiths are hacks.

I'm not disagreeing with anything you are saying. Sorry if it appeared that way. I agree with you. People should listen to those that know (like manufacturers or reputable gunsmiths), not random 'shadetree gunsmiths' that might be 'hacks'.

 

[dlbleak]

Rock river does