My .357 barrel has internal threads and the screw in "cutter" for the shot loads. Forgive me if there are better names. But what do I do when I'm not using it? Leave the threads exposed? Didn't get this barrel new so I don't know if I'm missing something but it doesn't seem like there's much room for anything to go in and protect the threads. Not that anything will contact them but it sure seems like they will get powder residue caked in them.