I use the PWS FSC30, and it reduced the recoil of the RFB almost to the level of recoil from a .556/.223! It's a great break for this rifle.
My hunter only came with the thread protector on it and it wasn't very tight.
I put a
SEI brake on mine before firing the first round out of it.
The U.S. Coast Guard uses them on their AR-10's so I figured they work well.
Stops muzzle climb dead and reduces recoil enough you can shoot it all day.
No vents on the bottom so you can shoot it prone without a face-full of dirt.
Produces a lot of side concussion blast for bystanders but not the shooter.
Birthday pic:
The main point to make is, that the RFB needs either a brake or suppressor to make it fun to shoot, not a flash-hider.