Just a guess, but did you ever try running one back through the .223 die? That's how they are made by running a .223 through the 7mmTCU die. I used to make my .22-.250s by running .250 Savages through the .22-.250 sizing die. May not work, but I'd try one.
Yes I did and it was actually funny. Crushed the shoulder like a pancake. Before I had a .223, I had hundreds of .223 that I necked-up to 7mm, stretching the neck out. Now I wish I had waited. I guess it is easier to stretch than compress. Thanks for the tip though.
Darr- actually 7TCU is made from .223 rem cases...
dednlost- now that would be cool! all the benefits of a larger bullet takedown while using the reduced amount of powder,less weight and size of a .223. I think you are onto something. Can an upper be made for a 7TCU?
Hey they make 6.8 and some other rounds for the ar don't see why 7tc wouldn't work and maybe better, it wouldnt surprise me if these newer rounds were developed just because of the not invented here syndrome if you know what i mean.