Strelok now banned/sanctioned in the US.

[hlee]

This would actually make a serious question, I think the difference is not really big but where exactly are we supposed to take this measurement? I assumed so far the center of the optic, where the adjustments are?

On a scope that is 16" long and using a 20 MOA rail, the difference is less than 0.1" from front to rear. I wouldn't get too wrapped around the axle over exactly where you measure the scope height.

 

[lash]

Oddly enough three of the more advanced sources don't even mention it; ColdBore, Field Firing Solutions and Sisk's articles.
All of them imply other sources of error such as incorrect click value and range uncertainty are more important.

The one print mention I can find is from AB and they say to measure it at the turrets. Given their emphasis and video on the subject of click value it makes sense, but I can also see where an aggressive scope cant might matter here.

Seems even Leupold agrees on turret not objective:

This is correct. I could draw a line diagram illustrating it, but probably won’t. The inclination of the rail matters not at all. Your zero is a meeting point for the imaginary lines going through the center of the scope and the center of the barrel.

 

[Schütze]

This is correct. I could draw a line diagram illustrating it, but probably won’t. The inclination of the rail matters not at all. Your zero is a meeting point for the imaginary lines going through the center of the scope and the center of the barrel.

… at the turret location?

 

[lash]

… at the turret location?

Yes.

 

[LeftyJason]

Height over bore doesn't matter that much as long as it is accounted for.

 

[Ronws]

Do you measure at the scope objective?

Center of scope tube (usually the meeting of the scope rings) to center of action. On most, this is the bottom of the ejection port.

 

[Tokay444]

It only makes sense to be the centre of the erector.