Brocock Ghost

ART is Daystate's Accuracy Research Team program. More background info on that available here:

https://daystate.com/stateoftheart/

I think that all of Daystate's ART barrels have been polygonally rifled, and don't know whether those are choked. But ART seems like components + a testing process, so I guess that any barrel design that tests out could end up being labeled as an ART barrel.