Out of the right barrel (and the rest put together right) it will do sub-MOA, at least with good supersonic loads - within reasonable distances for its velocity
You are right. With the right build, the right loads, with glass and in the right hands, sub MOA can be achieved. But from a round designed for suppressed SBR's who cares? If you really wanted a rifle for precision shooting at distance, 300aac is the wrong choice. For what the round was designed for, 2moa is plenty accurate. The barrel twist in most 300 barrels is wrong for the fast stuff, you might want to reach out with and the subsonics have such a wicked arc, they are the way wrong choice for targets any further than 150-200yds.