I finally put together my AR and wanted to roughly bore site the iron sights The sites are F2 FSB and Magpul MBUS Gen 2. I bought a laser bore sight that goes in the chamber. When I put the laser in the chamber and looks down the sites I cant see the laser light at all.... The laser is covered by the FSB. If I lift my head up a little then I can see the laser in between the ears of the FSB. I am stumped at this point. Do I raise or lower the front site?

Please inform me how to proceed. LOL

A lot depends on what range you are working at. Think about it. If you are sighting against a wall at any sort of close distance, the bore (and the laser) will be well below the line of the sights. Taken to the extreme, if the "target" is only a few inches away, there is no way you will ever be able to adjust the sights to see the laser. Get as long a distance as you can muster, and then try again. If the laser is still too low, you need to either lower the front sight or raise the rear sight (or both) to be able to see it.

At what distance is your laser dot when you are comparing to your iron sights?

You can't sit in a room indoors and expect to see your bore sight laser dot on the wall looking through your iron sights.

Laser bore sighs are only good to get you on paper with your first shot. They are not dead on accurate. In other words lining up your iron sights with a laser bore sight will not ensure that you can pop apples out of a tree at 50 or 100 yards.

I would start out at approx 25 yards or so, fiire, make corrective adjustments, re-check then go back to 50 yards. Once at 50 yards, fire, make corrective adjustments, re-check, fire until you are as close as repetitive as reasonably possible. You are now zeroed in at 50 yards.

HaHa... This is a great analogy... the rear sight is your friend it follows you.right to right left to left
the front sight is the enemy it runs away. up for down, down for up