Same that is good for any other rifle, and the same rules apply.
As long as you stay out of someones garage, there really are no "bad" barrel makers. Everyone has rockstars, everyone lets a turd slip out.
The masses at large aren't good enough to honestly know the difference between a "entry level" Vs. Christ's left hand. So support the company that you like, or that offers something you can afford.
The "worst" ER shaw that I have, which came with a tight-spot near the bore; will hold MOA at a mile. And lets be honest, if $250-450 is the end of the road for your wallet, you aren't concerned about absolute precision anyway.
Choose and enjoy.
Cheers
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