I have a LaRue 12.0 and gas block to be delivered today at my house.  I need to know how to install the gas block and have two questions.

1.  How do I align the gas port hole?  Is there a witness hole on top?

2.  How do I secure it?  Once I have it aligned correctly, do I dimple the barrel with a drill and secure the allen bolt with red locktite?

Just checking 'cause I want to crank this project out tonight.  One down, one to go!  

Thanks,

Corey

I aligned mine by putting a mark on the barrel shoulder just behind where the gasblock stops. The gasblock is designed so that you don't have to align it fore and aft as it rests against the shoulder.  You only have to worry about lining it up by rotating it.  Once you have the TDC (top dead center) mark on the barrel shoulder you can just rotate the gasblock until the hole in the hump (that sounds funny) lines up with your TDC mark.

I did not dimple my barrel as I don't have the tools (a drill press) to do it to my satisfaction.  If you're going to do it, mark the ends of the allen screws with a marker or something so that their location is transferred onto the barrel. Then disasemble the gasblock and drill the holes.  Make sure you get the holes drilled perpendicular to the barrel.

I've eyeballed every low profile gas block I've ever installed, including the handguard cap gap.  Don't overthink this too much, it's pretty easy.  Marks help, but after you've installed a few, a calibrated eyeball works just fine.

Setscrews with Loctite are just fine.  Dimples are better, but probably not needed in this application.

Blue loctite will work just as well and will make it easier on you if you ever want to remove it later on.

Do you need a drill press for dimpling the bbl or (if you're careful) can you use a hand drill?

Corey

Drill press is always the best choice, but if you like to walk on the edge, grab a hand held.  If the drill bit grabs, it may go a tad farther than you would like with a handheld.  Do I speak from experience - why, yes I do.

Quoted: Drill press is always the best choice, but if you like to walk on the edge, grab a hand held.  If the drill bit grabs, it may go a tad farther than you would like with a handheld.  Do I speak from experience - why, yes I do.

There's a difference between liking to walk on the edge and not having many other viable choices.  Of course the end result is often the same.  

Corey

PS  I'm not all that worried about the drill bits grabbing as all mine are so darn old I'm hoping that they'll cut into the barrel in the first place!

Personally I would NOT dimple with a hand drill.  I've learned many expensive lessons tinkering with ARs, but fortunately I haven't made that one.