Learn intended use first - Firefield Laser Bore Sight

I loved this product and I own two of them. I use it to bore sight every AR build that I assemble, and most pistols or rifles without muzzle devices.
My Instructions:
1) Bore sight before installing the muzzle device otherwise the magnet will not lay square to the bore
2) Bore sight at a distance of about 10 to 15 yards that will get "on paper 81/2 x 11 inch" at 25 yards. Sighting the gun after that is up to the shooter.
3) It is critical for the magnet sit flat against the barrel crown ... if the muzzle device is installed and is hard to remove, then do the following - only applies to AR rifles:
A) Separate the UPPER from the LOWER assemblies - If you need my instructions on how to do that please proceed no further.
B) Remove the Bolt Carrier Group (BCG) from the upper, keep the bolt extended forward (should be as it was extracted from the receiver)
C) Attach the laser magnet to the bolt face and center it with your fingers (they are about the same diameter size)
D) Turn the laser ON. Carefully re-insert the BCG into the receiver, but do not press or push hard, guide the BCG in and look for the laser to perfectly shine on any near wall surface. NOTE: The BCG will not go totally in as it has the laser attached to the head.
E) Move the BCG in & out until a perfect laser dot shines through the barrel against a wall.
F) If I have to explain how to sight your iron sight or scope .... proceed no further.
g) And this is how to BORE SIGHT a rifle.