When installing a low profile gas block on a typical AR-15, how necessary are the "dimples" in the bottom of the barrel?
I've seen them on my BCM barrel, but after working with a couple Aero Precision barrels and a Larue one, none of the others had the dimples for the gas block set screws to go into.
Should I be drilling these somehow on those barrels that don't have them? What kind of jig or whatever should be used to ensure the gas block is straight up and down, and the holes are proper?
Is red Loctite and tightening the fuck out of these "good enough" on barrels without the dimples?