Here's some gunsmiths who specialize in AR15 work. As of right now I haven't utilized any of them but they do come recommended from folks I trust. As usual additions and feedback of those listed is welcome and appreciated. Contact me.
Addax Tactical is recommended by the good folks at the AR15 Armory. Addax offers the following services for the AR15. Click the links below for more information.
Adco is one of the most often mentioned shop with a fantastic reputation for their AR15 work. So of their services are listed below.