The problem with knurling, in general, is that the metal displaced by the process will migrate back under load. Since the breech end of a barrel is subjected to some pretty strong shock and whip, I'd not expect it to be a good idea.
-A conclusion is not a destination, it's simply a convenient place to stop thinking.-
-Reading a thing doesn't automatically make it so; repeating it doesn't necessarily make it any truer.-
-Every Texan should be a member of the Texas State Rifle Association.