Take a look at this site. http://www.muzzlebrake.com/prd_mzb.html
I had them do my 300RUM in stainless and they did a beautiful job. They brake is VERY effective and the quality in workmanship can't be beat. When the brake is on, you can't even see the seam line. Plus, it also comes with the thread protector that you can use while hunting if you want. Best I could find when I was looking.