Riley, yes the Ruger ar556 comes with a threaded barrel with 1/2×28 thread pitch. A gunsmith shouldn't be necessary because a suppressor just screws on and off. Any suppressor with a 1/2×28 threads that's rated for 5.56/223 will fit. Hope this helps.

Riley, yes the Ruger AR-556 comes standard with a barrel threaded 12"x28. The only exception would be state compliant models, which have non-threaded barrels for those states who like to trample on your 2A rights. Have a great day!

Hi Riley, yes Sir it is threaded 1/2-28 tpi so you can easily add a silencer or suppressor no issue. Cheers and stay safe!

Yes indeed, as the guys have already mentioned below!
Now, I am unfortunately in a not so Free state so please enjoy yours!!

Ruger uses standard 1/2-28 for the AR-556, SR-556, Mini 14, and 10/22 threaded barrels. This is a standard thread size for .223/5.56. I hope this helps!