Scope Height ?

[heikki02003]

I have a question regarding "scope height" or "sight height" in PointBlank and JBM's Ballistics Programs respectively. What is it? How is it measured? What is its significance in ballistic calculations?

I know it is measured in inches and can assume that it takes into account different size objective lenses, main tubes, and ring height. My intuition tells me it is the height of the center of the scope above the center of the bore. Is this right? If so, how does one make a precise measurement of it? And, how critical is this measurement to accurate ballistics calculations?

Second part to my question is that I have a 10MOA forward base. How is this taken into account in the calculations?

Could someone please shed some light on this subject.
Thanks in advance.

 

[Preacher]

Your intuition is correct on the height.
Can't help with the other one 'O,

 

[heikki02003]

Hello Folks,
Could somebody please suggest a place in this forum for this question. I don't want to go repeating this question all over the forum, but I know a few people must know the answer. Somebody has to use ballistic calculators to their full potential.
It's kind of a hard one because it is actually a question about ballistics calculators. I asked this question in the Optics forum, but maybe it is an advanced gunsmithing or general forum question.
Does somebody know somebody that would know the answers to my questions, if so I could PM him/her.
Any help would be greatly appreciated.

 

[anyrange]

The sight height measurement is not that critical in ballistics programs. I normally just eye ball with a six inch scale and I am within twenty thousandths,.020) You can use a caliper and measure receiver or barrel diameter and scope tube or bell diameter and space between and then due the math. The 10 moa ranp is not any different then changing the line inside the scope. If your height of sight is within a 1/16 of an inch the program results for drops whould be within the bullet diameter.

 

[Fred Bohl]

Kyle

You are in the correct forum. I can't speak for the other regular posters, but I've had a busy four days with little time to work on your questions.

As you surrmised, scope or sight height for most of the popular ballistic programs assumes that height to be measured from the axis of the barrel bore to the optical axis of the scope or sights. Only the very high end,sophistication and cost) ballistic software makes any provision for the actual setting of the "zero" of the scope or offset mount angle.

Those that do include provision for you to input that data by calibrating the program by test firing at known ranges. this provides for calibration of "click" values, offset of the scope axis and actual load performance.

For the less sophisticated programs you can just input the scope axis height mid way between the rings. If possible get the out put data in MOA or convert to MOA and then subtract your mount angle in MOA from the predicted drop offset In MOA.

 

[mikecr]

I would just measure center to center,bore to scope) and enter that value. The MOA of scope bias wouldn't matter, because the software is going to give you elevation needed -beyond your biased zero.

 

[heikki02003]

Thank you very much to all those who took the time to reply. I now have a thourough and clear understanding of the subject.
This place is great!
Thanks again
Kyle