Originally Posted by dana bodnar
I read all of this now Iam really confused, and I dont want to take my rifle apart to find out. I need this to make sure my balistis charts have the proper information in them. It seems to me that it would be the center of the bore to the center of the scope.
You are correct..the OP was asking "how do you measure it". As far as the balistic charts, and you don't want to dissasemble your setup, then guess to within 1/2 inch...which is very easy, and you will be good enough.
With a 300 yard zero you are looking at an error of 1 inch at 1000 yards....the difference between 1.5 and 2.0 inch scope height using a 140 vld at 2900 fps.
The diff is a little greater if you use a 100 yard zero.... about 4 inches at 1000 yards. Pretty much a moot point!!
Good luck and don't sweat the small stuff.