Well, both in a way. The threaded barrel is for silencers and whatever threaded object you want to hang on the end of your gun, and you have to protect those threads when you have nothing on there. Ergo, thread protector. If you are not going to add a silencer or anything else, then dead weight, although there is not much weight with the extra barrel length and the thread protector itself. So, if you have no plans on adding anything, save the bucks and weight and buy a normal barrel weapon.