I built an AR pistol and decided it was worthless without a butt stock. Now that the brace rule is gone, I want to install a brace and put a sling on it. The butt stock has a flush cup system but the fore end does not. Is there a flush cup or adapter that can attach to my for end? If not what is the next best option? What sling would you recommend? Ive only ever used a hunting sling or a military type with all of the holes and hooks. Thanks