The size of the 5.56 is the same as the .223. Either will chamber; either will fit a magazine. The only real difference that is important is the length of the leade at the front of a rifle's chamber. It's a bit longer for the 5.56.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.