[Aguila Blanca]

I checked the current regulations for each of the states on the 2008 list. I had to remove Connecticut, Kansas, and Minnesota. Wyoming also allows ,223, BUT ... their regulation allows centerfire, 22 caliber or greater (except .22 Hornet), 60-grain minimum bullet weight, COAL 2" or greater. This means the M193 ammunition is not legal, because the bullet is 55 grains, but M855 is legal because the bullet is 62 grains.

So, bottom line is that centerfire rifles using .223 / 5.56x45 ammunition are still not legal in 10 states.