Ruger has recently introduced the threaded barrel versio of 22/45. It says the threaded is for muzzle attachment. What's it intended for? I wonder if Ruger also sell any muzzle attachment for this 22/45. What're the options? Silencer? Muzzle brake? I know it's a pain to get approval for purchasing a silencer. How about other accessories attached to the muzzle? Thanks.