Hi James and welcome. Yes it shoots both. Since the barrel is marked and chambered in 5.56NATO it will shoot 5.56 slightly more accurately. A Wylde barrel splits the difference between 5.56 and 223 chamber length and will shoot both 5.56 and .223 equally well. Cheers and stay safe!

Yes it will shoot both 223 and 5.56 ammo equally well

Good evening to you!! Yes the Ruger 556 shoots both 5.56 and .223. It will shoot both equally well. It's all about the shooter when it comes to grouping. Hope this helps, have a good day.