Reloading .223 Cal vs. 5.56mm

legion · 03-01-2009, 04:58 PM

First off, my AR-15 is chambered for 5.56mm NATO, so shooting either 5.56mm or .223 Rem is not an issue for the rifle.

I bought some used brass at the gun show yesterday. It was all supposed to be all Remington brand .223, but once I opened the packs, I found them to be a mix of brands with some .223 and some 5.56. I did check the packs at the show, but they were vacuum-sealed and seemed to be all the same brand/caliber there.

My question, is, can I reload the 5.56 brass with my .223 dies. It's my understanding that the only difference between 5.56 and .223 is that 5.56 has a longer neck. I was thinking that if I trimmed all of the 5.56 cases to .223 standards, then I would eliminated the difference and be able to reload the cases with .223 dies.

Thoughts?

excalibur43 · 03-02-2009, 02:29 AM

Don't know about the longer necks. They are the same caliber though.

JB55 · 03-02-2009, 06:59 AM

I reload both for my AR. You may have some issues loading brass that was fired in another gun.

Jeff

Prairie Wolf · 03-02-2009, 07:48 AM

I think the exterior dimensions are the same. I don't think the 5.56 cases are longer, although the throat on 5.56 rifles is longer.

I would check the capacity of the cases. Military cases tend to have lower capacity, so pressure would be higher.

You could sort the brass into two lots, and develop separate loads.

falcon · 03-03-2009, 03:48 AM

Quote:

I would check the capacity of the cases. Military cases tend to have lower capacity, so pressure would be higher.

I weigh my cases when real accuracy is needed.US military cases are not heavier (read thicker)than US made commercial cases.Some Brit military military cases are thick and heavy. Ditto for Lapua .223 cases. See Brass Weights:

http://www.ar15barrels.com/tech.shtml

Pete D. · 03-03-2009, 05:07 AM

Separate the cases by type, pretty much standard practice. Other than that, I would not worry about it. Load'em and shoot'em.
As long as you FL size the cases, you should not have any troubles. There is the possibility, though, that you might need a small base sizing die if there is any problem with the cases fully chambering.
Pete

Alaska338 · 03-03-2009, 06:06 PM

Better if its chambered for 5.56.......military loads are a little hotter...........than 223 Rem.

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