Since it has intrinsic overload, it can’t have anti barrier rounds. Bungie doesn’t like overlapping artifact mods with intrinsic champion stunning weapons.
OK I learned something new and clears up why other weapons I've tried don't work with an artifact enabled. That's where the descriptions confuse me. I thought the shotgun artifact applies to every shotgun but I can see having the ability to naturally stun overloads, allowing it to also stun barrier champions is too good to be true. Thx for the reply and info.