I want to install a Low profile gas block on my AR-15 I am building (6.5 Grendel) and I dont want to use the regular site post. I had ordered a Sabre Defense 18" Fluted barrel that comes with the front sight post and i want to replace so i could fit a longer free float handgaurd on it ( 12" Daniel Defense M4 Rail) cuz the barrel has a mid-length gas setup. I see most of the gas blocks have set screws and the barrel does not have the divots for any set screws, now im no gunsmith and i was wondering how hard it was to put divots on a barrel w/o fuckin it up or im just going to purchase the Daniel Defense Low Profile gas block that supposed to fit under that rail and it clamps on. What is the best way to go? Im thinkin to buy the D.D. Low Pro gas block cuz i dont want to ruin a brand new barrel.