5.56 NATO vs. .223 Rem.: What's the Difference?
Many popular AR-15 rifles on the market are chambered in 5.56 NATO or .223 Rem. Externally, both rounds look exactly the same, but there are some critical differences between the two.
Time and data have also unquestionably revealed that when compared to these semi-auto-pistol cartridges, the .357 Magnum does a better job at stopping bad guys.