Aren't 5.56 and .223 the same round?

[Robert]

I just hope you didn't also stick your son in his shirt backwards!

He does that on his own...

 

[RugerMcMarlin]

OK I'll play. Colt barrels are only marked 5.56 for foreign export. The domestic barrels are still stamped .223.

 

[Art Eatman]

This thread has become repetitious, so I don't really see any point in continuing...