I recently got ready to finish a build and needed to have a flash hider pinned and welded.  Went to the place from last year and they were gone.  I remembered  a thread from last year, and I had bookmarked Snipe Custom Arms.  Although primarily a shop for long range shooters, they are able to handle most anything related to ARs. I met George, and he was gracious enough to show me around their shop and examples of some of their work.  I am happy with the work they did for me.  They are at http://www.snipearms.com/services/ar-15-ar-10-m4-m16-m110/.  Their phone numbers are listed on the contact page, or if you send a message and have trouble with CAPTCHA  you can email George at George@Snipe Arms.com.