Thanks, nice image! If i ever come across the dies I will surely forward you the link.
From what i've been reading, on posts and here we go again, I understood 5.56 as being the chamber dimensions and .223 to be the cartridge dimensions. once you use that in your 5.56 chamber, like you stated earlier the cartridge is blown up
(figuratively speaking) to a 5.56.
So it makes sense that someone should make a 5.56 die to keep from working the case so much.