Anyone used the US Optics Boresighter? They don't push it, but they do recommend a magnetic type sighter like theirs for bore sighting.

The best bore sighter I ever used is my own eyes.

Get the rifle solid in a rest, and remove the bolt, look down the barrel from the breach of course at a target from 25-50-100 yds with a center dot or diamond and center it in the bore, then adjust the optics windage and elevation to it.

This goes for any rifle with a removeable bolt where you can look directly through the barrel from the breach. AR's/ Bolt guns ect:

Of coarse if you have something like an M14 then this not an option as far as I know.

May take a couple of tries, especially if your OCD. It worked like a charm every time for me.

I mostly do it at 50 or 100 yds.

For an AR?  Just pop the top and look down the barrel.  You don't need no stinking bore-sighter