I've always tried to get my scope reticle perpendicular with the bore to avoid inadvertent "windage" if a vertical adjustment is made. I've pretty much stuck with the 2 level method, and then used a bore sighter. It usually comes out pretty good. However, I recently came across this little gizmo, and wondered if anyone has any thoughts or experience with it. It looks like it has been out since July or so, so there's not many reviews on it. Just by looking at it, and how it rests on the barrel, makes me wonder just how perpendicular it can get with the bore since it doesn't actually level the gun. Thanks for any input.