I have KDF muzzle diameter brakes on my .300 Weatherby and my .375 RUM. The felt recoil of my .375 RUM was intolerable (to me) before I had the brake installed. With the brake, my .300 Wby kicks about the same as my .308 Win. The KDF brakes have holes all around the barrel, including the bottom, and I have shot both of these rifles extensively from prone positions both hunting and at the range without any problems. Yes, they kick up a little dirt and grass, but it hasn't been a problem.
