Generally, you want the brake to tighten against the shoulder.
If looks like the brake does not have a counterbore to account for the unthreaded portion of the barrel.
You could use a crush washer to tighten the brake against.
The cleaner method would be to have a gunsmith counterbore the back side of the brake and then trim it until it times up correctly on the barrel.
If you were in Los Angeles, I do this type of work.