I would like to get an 11.5" barrel and add a FH to make it street legal. I have seen many where the FH is already permanently attached. However, I don't like any that I have seen thus far. Ideally I'd like to get a barrel and a separate flash hider and attach them. My question is, what is the process? Does it HAVE to come attached? Can I permanently attach it myself? Do I have it sent to a gun shop and have them do it for me? Please help! Thanks.