Any disadvantage for .223 Wyde barrel instead of 5.56?

[Bfh_auto]

I would not want to be the person, but from a legal point of view that would be interesting. A manufacturing defect results in, what should have been a legal rifle, but results in a short barrel shotgun due to the defect. Would the ATF be reasonable, or go after the owner, or the manufacture, or both?

Considering no one makes 556 shot shells. I would think it would be OK. But I wouldn't bet on it.