.223 / 5.56 NATO

[9mmPatriot]

https://moriartiarmaments.com/image/catalog/pic1.jpg
https://moriartiarmaments.com/blog/223-wylde-vs-556-nato-the-common-misconception.html/article

 

[9mmPatriot]

Uncommon Sense: 223 Remington vs. 5.56 mm – The Definitive Article

 

[diyj98]

That's not necessarily true and may be brand dependent. Apparently, going by case weights, neither Federal nor Remington feel it cost effective to have two entirely different sets of case forming dies for a product with the same exterior dimensions. Per the linked article, any difference that might exist is about 1%-or less- of case volume.

I can't claim to have made a habit of measuring the thickness of the various manufacturers, but I have reloaded a great deal of 223 and 5.56 cases. The 5.56 cases I've loaded had had a slightly lower powder capacity than the 223 cases I've loaded. There are a number of articles stating that 5.56 has thicker brass, but I'm not basing my comment on articles, just my experience with the cases I've loaded.