new 6721

[fyrelt]

i got a new 6721 and i noticed that the lower is stamped 223 not 5.56 like my bcm and other colts,what gives,can i shoot 5.56 in this carbine.

[JSantoro]

From the stickied threads in AR Technical: https://www.m4carbine.net/showthread.php?55149-5-56mm-NATO-versus-223-Remington-Chamber-Differences