I'm planning on installing one of these on my next build. It will be installed on a new barrel with no previously installed gas block. I get the general premise that I clamp the sucker on using the four cap screws. The question I have is how do I align the gas block with the receiver? I would like to do something better than eyeballing it. Also, would it be recommended to use Loctite 271 (Red) on the cap screws or is there something more appropriate?

Thanks.

Easy way is cap off one end of the barrel and pump the other end full of air and listen/feel the air come out the gas block...easy and flawless.

Put the sight down and lay something flat and straight on it perpendicular to the barrel.   Do the same on the upper and from the rear make your two flats parallel.

Not too hard to eyeball. The bottom of the clamp on piece has a generous sized hole to go over the gas port. I put one on the Bushmaster I sold a few years ago with little AR experience at the time and it worked the first time out.

Follow the instructions posted on their website.
They don’t recommend Loctite.
I don’t use Loctite on gas blocks, other folks have different feelings about it.
If you are free floating the barrel pay especial attention to the part about leaving a gap where the handguard cap would normally go.

This .... I don't use loctite on GB's.

The gap is about 1/16" from the shoulder .... I use an old end cap that's been opened up with a dremel on one side to allow me to slip it in between the shoulder and GB for proper indexing.

They sell a rail vise clamp that lines up the rail perfect then you tighten it while in the rail vise for a perfect alienment. Cost about $61.00. (YHM) Some people use a clamp on hand grip or scope mount half on front rail half on back rail.