Because looking through a scope that is canted is annoying. If you don`t level the gun, then the scope will not be level.
Also a scope that is not level with the gun can cause the bullet zero to be off at 100 yards or more.
The proper way to mount a scope is to level the gun and the scope, so the cross hairs are level with the gun. So, my point was, bore sighters alone do not level the gun. I need a level that will work on all types of guns.
Henry - Life NRA Member, GOA Member
If con is the opposite of pro, is Congress the opposite of progress?