If you want to be particular... take a set of calipers then: measure the scope tube diameter, measure the receiver diameter, measure from top of tube to bottom of receiver, subtract 1/2 tube diameter and 1/2 receiver diameter = centerline of scope above centerline of bore. Then you have people who get all twitterpated over the difference in height between the fore and aft ends of the tube when using a 20 moa canted base, and try averaging the two measurements...
Close enough: Take a ruler, and eyeball it from the middle of the scope tube to the middle of the receiver (hint: the gas port on the side of the receiver just above the stock is a good reference), and get it w/i 1/4".
If you are bored, plug in different numbers (1.5, 2, 2.5) and see how much it matters (not much). 'Close enough' works pretty darned well.
I was really wondering if having a cant on the scope(ex. using a 20moa base) really changes how the program works. I know that the center of the lens to the center of bore is a fixed measurement. But if you had two rifles same cal. and such, same bore/sight ht, and both zeroed at 100 yards; but one uses a 20 moa base and the other has a level base. Will equal come-ups cause the same results regarding shot placement.
I've got Exbal and the same question as the original poster. Got a 0 moa base at the moment and am thinking of asking Seekins to make me a 10 moa base. But am not quite sure what the cant does to the program, if anything. If I recall correctly from similar past discussions, the cant doesn't matter, but I'd sure appreciate a refresher on this...
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Thinking out load, I think that it should be the height of your eye ,as you look through the scope, above the centerline of the barrel.
IMO, you normally use scope height because the scope is at 0 degrees, and so is your eye.
I'll go to the far edge of my thinking on this one.
All things being equal, exactly equal, except for the cant of the base, after 100 yd zero is precisely set, the zero settings on the elevation turret will differ. However, the number of clicks for a given yardage other than the 100 yd zero will be exactly the same. Right on the money IMO.
I've never tho't that far ahead, thus any corrections would be appreciated. That makes two of us.
Me thinks it "has" to be that way or MOA per click would vary with the scope cant.:confused:
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