That looks like a thread protector. Its not a brake.
How long is the barrel? If its not pinned and welded, it should come off, and a proper brake can be put on. If it is pinned and welded, and the barrel is shorter than 16", then youll have to have the brake pinned and welded in place. If its 16" and over, you can just replace it, as long as that doesnt violate any of your state laws.
This is my Saiga conversion with its brake. It has a 14" barrel, so the brake is permanently installed.....
