How to measure scope height from bore

[Koda]

I want to estimate drops at distance in a ballistic calculator but need to know my scope height from the bore. How do we precisely measure scope height?
In my case a bolt action rifle but I wouldnt mind knowing this for an AR or Ruger 10/22 as well but right now my primary interest is the bolt action.

thanks..

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[bcp]

Bolt action: Distance between bolt and scope tube + 1/2 scope diameter +1/2 bolt diameter. Or substitute "barrel" for "bolt" if easier.

10/22: Distance between barrel and scope tube + 1/2 scope diameter +1/2 barrel diameter.

AR: same idea.

Bruce

 

[Koda]

Bolt action: Distance between bolt and scope tube + 1/2 scope diameter +1/2 bolt diameter.

Bruce

Like this?

 

[solv3nt]

Like this?

View attachment 1339609

Nice watch!

 

[msgriff]

+1 on bcp's post. Your pic is correct, but with the angle of the calipers it won't be exact. It's probably close enough though.

For catalog listings or manufacturer specs, most scope ring/mount heights are measured from the base to the center of the ring. You can also measure from the base to the bottom of the ring saddle and add 1/2 the tube diameter. For AR's, add that number to the following centerline of bore to the top of the Picatinny rail measurements :
AR-15 ~1.215"
DPMS low ~1.253"
DPMS high ~1.313"
DPMS target ~1.638"
ArmaLite AR10 ~1.318"
(These were mostly measured or verified by myself and are not represented as a spec, but are very close.)

 

[Dogfacedpony]

Useful. I was just listening to a buddy on how he was having difficulty doing this. I didn't have experience enough to make a suggestion.

 

[Koda]

You can also measure from the base to the bottom of the ring saddle and add 1/2 the tube diameter. For AR's, add that number to the following centerline of bore to the top of the Picatinny rail measurements :
AR-15 ~1.215"
DPMS low ~1.253"
DPMS high ~1.313"
DPMS target ~1.638"
ArmaLite AR10 ~1.318"
(These were mostly measured or verified by myself and are not represented as a spec, but are very close.)

How do you measure these on an AR?

 

[Koda]

@bcp thank you, this worked on my bolt rifle.

Though I dont think it will work on all bolt actions and I cant see how it would work for AR style rifles. Would love to learn how for an AR...

 

[Ura-Ki]

@bcp thank you, this worked on my bolt rifle.

Though I dont think it will work on all bolt actions and I cant see how it would work for AR style rifles. Would love to learn how for an AR...

Take a long enough strait edge and lay it across the sights for open sights, for scopes, the use the same idea as the bolt rifles!

 

[msgriff]

How do you measure these on an AR?

You can get the dimension from the blueprints/TDP, but it's not directly spec'd.
For actually measuring, remove the BCG and measure the diameter of the upper receiver bore at the rear, then divide by 2. Measure from the top of the upper receiver bore at the rear to the top of the Picatinny rail and add the two.

 

[Koda]

You can get the dimension from the blueprints/TDP, but it's not directly spec'd.
For actually measuring, remove the BCG and measure the diameter of the upper receiver bore at the rear, then divide by 2. Measure from the top of the upper receiver bore at the rear to the top of the Picatinny rail and add the two.

that helps, will give this a try. thank you.