Differences between reloading for .223 and 5.56?

[BAC]

So I'm finally sorting out the odds and ends needed to start reloading, but an interesting question was posed to me and has made me pretty much stop in my tracks. Is there a difference in reloading for .223 and 5.56? Are there 5.56-specific dies and whatnot? Would using .223 dies on 5.56 brass change or alter the brass in any way?


-B

[markm]

No difference. Dies are .223.

Unless you have to reload your own defensive ammo, I can't figger out why anyone would want full throttle 5.56 pressures for practice ammo anyway.

[BAC]

So the difference in brass is so nominal that the dies wouldn't do anything at all? That's good to know. I've got some SS109 and once-fired Lake City 5.56 brass on order (not great, but dirt cheap), so I didn't know if the .223 stuff would change the way we'd need to reload. If not, good stuff. (Now I need to strongarm a local source for H335, Ramshot TAC, Reloader 15, and figure out primers!)


-B

[markm]

So the difference in brass is so nominal that the dies wouldn't do anything at all?

Pretty much. Mill brass has slightly more internal case volume. I use the same loads for every kind of brass I get... and that's a lot of different kinds.

[BAC]

Great news. Thanks markm.


-B

[US Autoweapons]

Pretty much. Mill brass has slightly more internal case volume. I use the same loads for every kind of brass I get... and that's a lot of different kinds.

I believe the case volume in 5.56 brass is SLIGHTLY LESS than 223. The 5.56 case walls and web are thicker reducing volume of the case while maintaining the same external dimensions.

[chadbag]

I believe the case volume in 5.56 brass is SLIGHTLY LESS than 223. The 5.56 case walls and web are thicker reducing volume of the case while maintaining the same external dimensions.

yep -- external dimensions are the same. most 556 brass is thicker in key areas so would have less capacity and would also be loaded with slightly less due to the small case volume driving up pressures

[markm]

Absolutely WRONG!

Molon (a member here and TOS) debunked that myth with the water volume test.

I think that is true for Mil 7.62 brass. But it is most definitely FALSE for 5.56 brass.

[markm]

If you scroll down here there's some data on internal volume of various brass. (H20 capacity)

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

I forget what Brass Molon tested, but these various brasses are pretty much the same with some of the Mil brass being slightly larger as far as internal volume.

[Hound_va]

The article is somewhat unclear. In the beginning he says "Military 5.56x45 brass often, but not always, has thicker internal construction, and slightly less capacity than commercial .223 Rem brass".

Then he goes on to show LC 04, 06, and WCC 99 brass having equal or slightly greater case capacity.

Based upon the first statement, one would believe that the majority of military 5.56 would have less internal capacity then commercial .223. It seems to me that his data in the case capacities chart posted does not clearly support that statement. As to whether the statement or the data is somewhat erroneous would be difficult to say based solely on the info presented in the article.