Gunsmithing Big Bore Muzzlebrake Source?

We have 3/4-24 brakes on the shelf that are setup for 338's and smaller. It's an easy change to increase the aperture size for you to run it on a 375. The brake is a 4 port that does very well on 33's and 37's

If you're looking for more than that then you might try Warner Tool Co.