BudsGunShop.com - Chambered to fire

Correct, you can shoot both 5.56 & .223.

Correct Sir! As a general rule 5.56. chambered guns can safely shoot 5.56 & .223. .223 Chambers should only shoot .223 due to higher pressures in 5.56 rounds.
223 Wylde is a unique chamber that will safely fire both (I.e. is built to withstand 5.56 pressures) but will be able to pull higher accuracy out of the .223 ammo.
I just got a Springfield Armory Saint Edge ATC in 223 wylde. Reviews on this precision AR go over the accuracy fine points.

Hi Stephen and welcome. The .223 Wylde is a hybrid chambering between 5.56 and .223 that allow either to be fired with minimun accuracy loss. Cheers and stay safe!

Hi Stephen, yes sir, all guns chambered in .223 Wylde can safely shoot both .223 and 5.56, no issues.
Stay safe & have a great day!