A friend of mine designed and produced a highly effective muzzle brake for .50cal use and then scaled the design down to smaller calibers. I still have two of them and they are the most effective, least noisy, (to the shooter) brakes I've used to date.
When tested on my 300winmag with a 208gr bullet it went from 35ft-lbs of recoil with no brake, to 10 with the brake. He put some sort mathematical equation to it and determined it was 98% effective at eliminating recoil from gasses exiting the muzzle.
More to the point, I told him he should try for a patent and sell them. He said there wasn't much point in going through the trouble to obtain a patent only to have someone copy it and change one minor detail to get around the patent. Indeed, all is fair in love and war.