Trust is a dangerous game! I'm sure the concentricity is within some tolerance...but what that is, who can say until you actually measure. And the manufacturer's muzzle brake will be designed around those tolerances. Looser the tolerance at the threads, means larger the brake bore...(for safety and liability issues).Back to muzzle devices- can you trust factory threads on a barrel to have concentric ID to OD parameters? or as @Susquatch pointed out would the factory care about such tolerances?