I hate to break it to you all, but when it comes to a .223 marked barrel, you can't go by the barrel marking.
I have a Mark X Mini Mauser factory marked ".223 Rem" but it is a NATO chamber. I understand that Olympic or some other AR maker did the same thing on some rifles.
Even some Colt rifles were marked that way.
In some European countries civilians are not allowed to possess military ammo.
That's probably why that Mini was marked that way.
