.750 Micro gas block

Actually came with 3 set screws. On a 20" Grendel 6.5 barrel - remove the gas end set screw, slide the block onto the barrel to the shoulder, rotate the block so you can see the gas hole in the barrel - thru the empty set screw hole - they line up dead on. Mark the barrel with a pencil centered on the set screw flat, rotate the block to correct orientation and center the upper portion of the gas block on the barrel mark and tighten set screws. You can mark the end of the gas block centerline prior sliding it on the barrel. You should get full gas port with this method.