Im not a pro gunsmith, just attended Colt Armor school this yr and would say yes turn it down, thread it, and install. I was considering the same operation on my 6400C barrel and decided to leave it as it is. Shooting BH 75gr match ammo at 200m hit -1.0 moa (on a bag). With that my 6400C will remain as it is. I FF with a YHM 4 rail and installed a Vltor standard and Im very happy. The lug and hiders dont mean anything, just add weight. The compensator on the 6400C is actually a proven well liked design which was written off as a compensator for the anti-gun nuts but is actually a flash hider in disquise if you knew it. Just something to think about!