Hello folks. I am contemplating in between the .223 and the 5.56 NATO for my DPMS M4. I have been using the .223 by PMC regularly and have been satisfied with its performance and accuracy. It is also cheap, $9 for a box of 20. I stumbled upon the Federal 5.56 selling for only $6.50 a box of 20. They're cheaper so I am considering buying it instead. Are the 5.56 NATO any better in performance than the .223 ammo?