Measuring sight height
One major rule with External ballistics is that if you input rubbish values  you’re going to get rubbish values back out again
An important but often overlooked value where this is true is ‘sight height’
So here’s a quick guide on how to measure it:
 Locate calipers

Measure diameter of scope  then halve it to get the radius So here my scope diameter is 65.14mm and so halved is 32.57mm

Measure diameter of barrel (be sure to measure barrel width in line with where you measure scope width as barrels are often tapered)  halve this to get the radius My barrel diameter is 27.7mm and so the radius is 13.85mm

Measure the distance between the barrel and the scope The distance between the two for me is 2.43mm

Finally add the gap distance to the scope radius and the barrel radius  Which gives you the distance between the centre of the barrel to the centre of the scope. So for me 32.57 + 13.85 + 2.43 = 48.85mm which is 1.92in
 Write that number down  it’ll be handy in future!
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