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Measuring scope height

ArmyJerry

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Nov 22, 2012
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I am starting to stretch out my shooting now that I moved to No Va, shooting at Peacemaker. Up until now I been just adding ring height barrel diameter / 2 base height to get my total height. Is there a more accurate way to measure scope height for a better ballistics calculation?
 
I am starting to stretch out my shooting now that I moved to No Va, shooting at Peacemaker. Up until now I been just adding ring height barrel diameter / 2 base height to get my total height. Is there a more accurate way to measure scope height for a better ballistics calculation?
I just open the bolt to the point where it is even with the back of the scope then use calipers eyeballing center to center.
 
Pull your bolt back to even with your scope's ocular lens. Get out your calipers and measure from the middle of the firing pin to the middle of your ocular lens. That is the scope height you enter in to your ballistic calculator.
 
Measure your bell diameter. Measure the gap between your bell diameter and the barrel. Measure your barrel diameter at that point.

(Bell Diameter/2) + Gap + (Barrel diameter/2)= scope height. If you measure with calipers you will be within .010".
 
Measure your bell diameter. Measure the gap between your bell diameter and the barrel. Measure your barrel diameter at that point.

(Bell Diameter/2) + Gap + (Barrel diameter/2)= scope height. If you measure with calipers you will be within .010".

Similar method - Measure bolt diameter/2 (Bolt should be dead center of the bore), gap, tube diameter/2. Easy greasy....
 
If you have a scope base or scope mount with a slope (i.e. 20-MOA), then you'll want to measure from the center of the erector housing to the center of your bolt. The more slope, the more error if you measure from the from or back of the scope.
 
Keep in mind that a 0.1" error in scope height measurement, with a 100 yds baseline zero, only means a 0.9" error at 1000 yds, or 1.5" at 1600 yds.
Since this small error is so small compared to POI variations due to the accuracy of the ballistic program and the effect of real world conditions on a given day, don't worry too much about it ;)