Measuring Scope Height Above Bore

[harro]

OK

Probably a stupid question, buttt……

What is the easiest way to get an accurate measurement of Bore to Scope height to get an accurate input for my Ballistic Calculator ?
How accurate do you have to be ?
I assume it means center of Bore to center of scope ?

 

[L1986]

Measure diameter of receiver and half that number
Measure distance from top of receiver to bottom of scope ring
Scope tube diameter cut in half

Add all three numbers together

I don’t think it needs to be to the thou or anything but I could be wrong.

 

[RufusBuck]

I had this same question. I was told to take my calipers and measure from center of the barrel at the receiver (the little hole) to the center of my scope tube.

 

[Coyotefurharvester]

Center of the bolt(in the receiver) to center of scope tube or center of windage knob should get you pretty close.

 

[BoydAllen]

This is how I do it. Using the back of my dial caliper, I measure from the top of the scope objective down to the top of the barrel (with the caliper extension against the front of the scope (taking care not to scratch anything, then I measure the diameter of the objective right at the front, and the diameter of the barrel where the caliper touched, then I subtract half of the objective diameter, and add half of the barrel diameter. It takes longer to write than do. BTW this number will be correct for any scope on that rifle with those rings and that base, and if you change to a different height of rings on the same rifle, with the same base, all you have to do is add or subtract the difference in ring height.

 

[std7mag]

Ballistic calculators use the distance from the objective lense.

Measure barrel diameter under objective lense and devide by 2.
Measure outside of objective lense and devide by 2.
Measure distance from barrel to bottom of the objective lense.

 

[Krogen]

Ballistic calculators use the distance from the objective lense.

Measure barrel diameter under objective lense and devide by 2.
Measure outside of objective lense and devide by 2.
Measure distance from barrel to bottom of the objective lense.

Actually, it's the line of sight to the center of the bore at the muzzle. Of course this is nearly identical to measuring at the scope objective unless you have a lot of elevation built into your scope rail.

Having said all this, typical scope height variations don't have much effect on trajectory. Try running your external ballistics program with various scope heights and you should see what I'm saying. IMNHO, muzzle velocity and ballistic coefficient variances have more effect.

Just my 20 m$ . . . .

 

[6.5 forever]

Center of the bolt(in the receiver) to center of scope tube or center of windage knob should get you pretty close.

I do this^^^^

 

[Mike Casselton]

I do this^^^^

That's exactly how I do it.
No reason to complicate it any further.

 

[Mike Casselton]

To be more specific, I go from the hole to the split in the scope rings. Done

 

[Hal]

Easiest way is to measure from the stock line to the split in the scope rings.

Hal

 

[Bill Norris]

Center of bore to center of scope tube works for me.

 

[Kracken McGraw]

Center of bore to center of scope tube works for me.

That and a yardstick I have hanging on a nail.

 

[Coyotefurharvester]

Wait until you play with a digital display scope(thermal/NV). Totally different ballistic arc, than traditional scopes. You have to shoot your setup every 25 yards, to graph out what will be the best zero for your average shooting distance. Mainly due to the height of the units, and the x,y axis shift of actually adjusting zero.

 

[std7mag]

Actually, it's the line of sight to the center of the bore at the muzzle. Of course this is nearly identical to measuring at the scope objective unless you have a lot of elevation built into your scope rail.

Having said all this, typical scope height variations don't have much effect on trajectory. Try running your external ballistics program with various scope heights and you should see what I'm saying. IMNHO, muzzle velocity and ballistic coefficient variances have more effect.

Just my 20 m$ . . . .

Most of my rails have 20MOA.

Using Strelok Pro, I followed the directions that they give to find the scope height.

 

[Jarhead6870]

Pressure relief hole to center of scope tube measured with a tape measure. Plenty close enough

 

[Ackman]

Center of the bolt(in the receiver) to center of scope tube or center of windage knob should get you pretty close.

Easy peasy, works beautifully. But apparently too easy for people who like to do things the hard way.