Confused

[Ala Dan]

Howdy Again My Friends-

I'm a bit confused about the caliber designation of the most popular so-
called "evil black rifles". In other words, what is the difference in caliber
designation between .223 Rem and 5.56 NATO. And, can rifles chambered
for one actually fire the other? For instance, can my 16" barrel COLT Match
Target Competition weapon (which is designated as a true .223) fire all
cartridges with the headstamp designation of 5.56mm? Is it in any way
harmful too do such? Many thanks in advance for the expert advice
that we tend to get from our THR membership~!

 

[dstorm1911]

WOW, 10,456 posts and ya have never read a single thread on here regarding .223 and 5.56x45??? not to mention proud long time member of 6 other sites including a gunsmithing site??

 

[Evenflo76]

http://www.6mmbr.com/223rem.html

Short answer: 223 OK in 5.56 rifle. 5.56 not safe in 223 rifle.

Long Answer is in Link:

 

[Monkeybear]

5.56 is loaded to higher pressures than .223 but when you get right down to it, and I'm sure some of ya'll disagree with me, any newly manufactured rifle should fire both safely.

 

[TexasRifleman]

http://ammo-oracle.com/

Everything you ever wanted to know about anything .223/5.56

http://ammo-oracle.com/

 

[Zach S]

You need to look at the bbl stamp, not the caliber marking on the lower. I've seen several Colts that said .223 rem on the lower, yet had 5.56 NATO stamped into the bbl.

 

[Ala Dan]

Many thanks folks, I will read and head if necessary~!

For inquiring minds, my posts of over 10,000 mostly deals with
handguns; and VERY FEW long guns~!

Update: I just checked the old Colt, and just as stated its marked
as .223 on the lower; and 5.56 NATO on the barrel. Good info like
this is what makes THR my #1 website.

 

[sarduy]

WOW, 10,456 posts and ya have never read a single thread on here regarding .223 and 5.56x45???

that was the first thing that crossed my head but hey...i have't read a lot about shotguns shells ...


to keep it simple, you can shoot 223 in a 5.56 chamber, but if you 5.56 in a 223 chamber, you "may" get some problems in the long run, just try some 5.56 and if they work good, then you are good to go.

 

[Zach S]

For inquiring minds, my posts of over 10,000 mostly deals with
handguns; and VERY FEW long guns~!

Yeah, when I saw your user name I thought I was in one of the handgun forums...

 

[jkingrph]

I have been shooting 5.56 in my 223 Rem mod 700 varmit special since I purchased it. I purchased it for exactly that purpose in 1970 when in the Air Force and could get ammo. The gunsmith that got it for me did not think there would be a problem and in 38 years of shooting there has not been any.

 

[TexasRifleman]

The gunsmith that got it for me did not think there would be a problem and in 38 years of shooting there has not been any.

That doesn't mean it's safe for all rifles. SAAMI still specifically says not to do it, so the thing to keep in mind is you MIGHT blow up your gun.

Most people never have a problem but it still goes against all the industry standards to do it.

I've done it too in a similar rifle, but if I blow myself up it's all on me

 

[dmazur]

Here's another link that may have information not already covered -

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

After a bunch of general information, there is a section on 5.56 vs .223 that seems to answer your question.