Rifle Scopes Sight height question

[GhengisAhn175]

Fellas,

When inputting into a ballistic calculator the sight height #, is that basically the height of your rings ie: NF rings & 1.125" = sight height?

Also the offset; that only matters if you have canted sights?


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[6Dasher]

Centerline of the bore to the centerline of the scope.

Offset: If the scope is not directly over the centerline of the barrel (ie left or right).

 

[GhengisAhn175]

Dasher, centerline of scope from the obj size right? Or it doesn't matter which end


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[lash]

Ghengis,
The center-line of the scope is the same no matter which end you use. In your case, since you know your ring height (which usually is the height from the center-line of your scope to the top of your rail), you can measure from the top of the rail to the center of your bore and add those two heights to get your number to input.

 

[GhengisAhn175]

Thanks for that lash. So if I understand correctly,

1. Ring height (I have NF ultralite 1.125") +

2. Center line of bore from top of rail (how do I accurately get this without using a ruler and eyeballing?)


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[lash]

That is correct.

I used calipers and a bit of the calibrated eyeball. Unless you are shooting extreme long range shooting, your dope should not be affected that you will notice if you are off by 0.10" or less. A more accurate measurement would have to involve better measuring tools and some careful measurements using extra props.

Remember that it's fair to assume that the center-line of your bore is in the exact center of your barrel, even if we do all know that there is realistic variation of some very small amount. So the measurement can be done using the outside dimension of your barrel divided by two. In other words, measure from the top of your rail to the bottom of your barrel and subtract half the barrel diameter. Then add that result to your ring height.

 

[haroldwilson]

Determining Scope Height Above Bore within AccurateShooter.com

 

[jdr724]

(Barrel diameter/2) + distance top of barrel to top of rail + height of rings = Scope height

measure barrel diameter right where is comes out of the rail and measure barrel to rail in the same spot.

 

[GhengisAhn175]

Roger this guys thanks .
Simple search also helped x.x

But I learned that the scope mount height is from rail to center of the scope!


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[Captain Kirk]

Scope height is from centerline of bore axis to center of scope. In reality, it makes very little difference as far as the ballistic program goes, pay with the #s and see the effects for yourself.

 

[Captain Kirk]

took this pic many years back while discussing the same topic

 

[GhengisAhn175]

Just making sure that I'm doing this right. Center of ring (where the two halves meet) and bottom is the bottom of the rectangular opening where round ejects from.

I get a total of 2.766




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[Captain Kirk]

Just making sure that I'm doing this right. Center of ring (where the two halves meet) and bottom is the bottom of the rectangular opening where round ejects from.

I get a total of 2.766

closer to center of the ejection port, or centerline of bore. That's the # you need. after you input that, change the height +/- in your app and see what happens.

 

[6Dasher]

OMG, something so simple made so difficult.

 

[damoncali]

Technically, it's the distance from the sight line to the bore centerline at the muzzle. Practically, put in 1.5-1.75" and be done with it.

 

[haroldwilson]

took this pic many years back while discussing the same topic

This is CFE. It is all you need.

 

[n2fooz]

Ghengis,
The center-line of the scope is the same no matter which end you use. In your case, since you know your ring height (which usually is the height from the center-line of your scope to the top of your rail), you can measure from the top of the rail to the center of your bore and add those two heights to get your number to input.

Not if you have a 20 MOA mount it isn't. The scope is canted with the objective closer to the barrel.

 

[Rob01]

Not enough to matter. Measure center bore to center of windage knob and be done with it. No long math problems needed.

 

[lash]

Not if you have a 20 MOA mount it isn't. The scope is canted with the objective closer to the barrel.

As previously mentioned multiple times. It makes so little difference if you're off by a bit, that your detail (while technically correct) is negligible and a moot point.

 

[n2fooz]

...technically correct...

Thank you

 

[n2fooz]

Not enough to matter. Measure center bore to center of windage knob and be done with it. No long math problems needed.

Thanks. I was wondering about this yesterday and this method would actually cut the difference by half.

 

[PlinkIt]

KISS keep it simple stupid...

Just get a rough measurement and roll with it, I'm not a pro but the rough measurements haven't led me wrong yet.. Eyeball it and move on without worry