# How do you correctly measure scope height?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Parkerb14, Feb 19, 2011.

1. ### Parkerb14Well-Known Member

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Jan 26, 2007
Title say is all, just wondering after reading "lets argue bcs". It had got me thinking, and would like to correct it because i just left it at 1.5"

2. ### rscott5028Well-Known Member

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Apr 18, 2010
I don't know if this is the proper way to do it.

But, I close the bolt about half way and try to measure from the firing pin to the bottom of the scope tube with calipers. Then add the radius of the scope tube.

That method is probably good for ~+/- .1".

It get's me on target out to 1k without having to fudge the Berger G1 BC much.

But, I'm keen to know of a better solution.

thanks!
Richard

3. ### BrozWell-Known Member

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Feb 3, 2007
I take 1/2 the barrel diameter at the shank, plus the distance from top of barrel to bottom of ring where scope sits then plus 1/2 of tube dimension.

Most of mine are in the 2.0 to 2.100" range with a NXS scope.

Jeff

4. ### bowhunthardWell-Known Member

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Sep 5, 2008
I use the measure and subtraction method. Most actions are round so it works fairly well, I guess you could also measure from the barrel right in front of the recoil lug.

Measure from top of scope tube to bottom of action (or barrel) = A
Measure scope tube diameter and divide in half = B
Measure action or barrel and divide in half = C

Formula is A minus B = X, X minus C = center of bore to center of scope, fairly accurately too.

You must take all measurements on the same place horizontally, i.e. don't measure the action and scope tube for A, the scope's objective bell for B, and the end of the barrel for C.

Most of my scope heights are about 1.7 - 2" using this method.

Ha Ha, guess someone posted same method while I was typing mine, lol.

Last edited: Feb 21, 2011
5. ### kemen4Member

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Dec 20, 2006
Take 1/2 diameter of the bolt, add 1/2 diameter of the scope tube and then add the distance from the top of the closed bolt to the bottom of tube.

6. ### Parkerb14Well-Known Member

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Thanks guys seems simple enough. Doesnt matter if it affects my BC or not in my 250 because im going to start loading some 53vmaxs when i can get my hands on some instead of the 52 amax...much better BC