223/5.56 question.

[harmonic]

I recently bought an AR chambered for 5.56x45 mm. I understand I can use 223 rounds. I also understand I can use the same reloading data for either 5.56 or 223.

But what about dies? Can I just use 223 dies to reload 5.56 cases?

Thanx.

 

[ants]

There is no difference. They are the same cartridge.

The only difference is that military specifications call for hotter loads in 5.56x45 (milspec contract ammunition not bound by commercial standards) and overall length is often very specific.
Commercial .223 Remington meets SAAMI commercial standards, nothing more.
But obviously that doesn't matter any more when you reload them, does it!

Someone will come along soon and help you with a link to the AmmoOracle or AR15.com site with clarifying information.

 

[IDriveB5]

5.56 has a smaller case capacity, therefore, with the same amount of powder, you will have a higher pressure.

For everything you need to know about .223 Rem and 5.56:

www.6mmbr.com/223Rem.html

 

[kelbro]

The Sierra manual has separate sections for 223 bolt guns and 223 AR-15 rifles. Different loads. Be safe!

 

[P-32]

5.56 has a smaller case capacity, therefore, with the same amount of powder, you will have a higher pressure.

Be aware Federal brass weighs more, ie, smaller case capacity than Lake City and about every one else except maybe Lapua. There could be some GI brass which has a smaller case capacity, but I have not found this in 223/5.56 brass. 308 and '06 is a different story.

The rifle will never know you are using 223 dies for your 5.56 chamber.

 

[rcmodel]

5.56 has a smaller case capacity,

Maybe it does, and maybe it doesn't.

You could always count on it with 30-06 & .308 GI brass.

But you can't count on it with 5.56 GI brass.

I have a lot of old LC 5.56 that is lighter then new .223 Remington commercial I bought a couple of years ago.

Only sure way to know is size, trim, and weigh it.

rcmodel

 

[EHL]

Not to jack the thread but,.... I too have this question. Is there a specific die set for 5.56 or all they one and the same with .223 dies?? (Similar to 45 acp dies and 460 Roland using the same or 40 SW and 10mm dies or 38 special and 357 mag)

 

[rcmodel]

For reloading purposes, 5.56mm and .223 Rem cases are exactly the same thing except for the headstamps. There is no differance whatsoever like the examples you named..

Nobody makes reloading dies specific to the 5.56MM, except the military arsenals perhaps.

The differance is in the chamber dimensions of the rifles.
The 5.56 chamber is very slightly looser then the .223, with a much longer leade or free-bore for long tracer bullets, combat dirt, etc.

rcmodel