Does Ruger or any other manufacturer make a muzzle thread protector that would be compatible with the diameter and thread on the Go Wild American Predator if you wanted to remove the existing muzzle brake? My rifle is in 243 Win.
The Ruger web site lists the "Thread Pattern" as 5/8"-24, so I'm guessing any 5/8"x24 thread protector would thread on:
ruger.com
If you want to be sure it looks nice, you could call Ruger and order the factory thread protector (looks like some of the .243 Predators come from the factory with them). Alternatively, you might want to get 2 additional measurements: the length of the threaded section and the diameter of the barrel, just before it steps down to the threads. Midway USA lists a bunch of different thread protectors, and you might find one the right length and diameter to match the end of your barrel. I purchased a Ruger 10/22 that came without a thread protector, and after measuring length & diameter, got one from Midway (apparently intended for a pistol) that fit great!