You mean the 5.56x45mm NATO/.223 Rem round?
Within close quarters combat (<50 yds) anything that will expand rapidly will do and bullet weight isn't important as at that distance anyting will be accurate enough out of any twist barrel...Unless you are referring to sniper shooting then what is rated for your barrel is the only thing to bother shooting...
Within close quarters combat (<50 yds) anything that will expand rapidly will do and bullet weight isn't important as at that distance anyting will be accurate enough out of any twist barrel...Unless you are referring to sniper shooting then what is rated for your barrel is the only thing to bother shooting...