How do you confirm it's zeroed?

[Alan]

After mounting an optic, what checks do you perform to make sure everything is perfectly intact?

 

[d2wing]

On most rifles I bore sight by sighting down the barrel at a distant object and adjust the scope to match. I use levels to make sure the center of the scope is perpendicular to the bore center and not canted. For guns I can't bore sight I use a laser tool. I usually confirm at 25 yards and for centerfire rifles, zero at 100 yards on a range.