Hi Charles and welcome. The barrel is stamped 5.56 so it will shoot either 5.56 or .223. It the barrel was stamped .223 then that would be the only recommended ammunition to fire. Cheers, stay safe and enjoy!

Hi Charles, if the barrel is stamped 5.56, it will fire BOTH .223 and 5.56.
If the barrel is stamped .223, it will fire ONLY .223
Stay safe & have a great day!

A barrel chambered in 5.56 can most definitely, all the time, without a Doubt, shoot .223 as well.
But, if it were chambered in .223 then you could not shoot the 5.56 round as the barrel wouldn't take the higher pressured round.

5.56 will shoot .223.

if it chambered for 5.56 it can use the weaker .223 with no issues you can not use 5.56 in a gun chambered for 223