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- Thread starter ar1458
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This data would be the distance in inches between the line of bore and line of sight.

To get this:

- measure the diameter of the scope end bell at the end.
- measure the diameter of the barrel at the end of the scope end bell.
- measure the distance between the top of the end bell and the bottom of the barrel at the end of the end bell.
- Subtract 1/2 of end bell diameter AND 1/2 of the barrel diameter from the top of end bell to bottom of barrel measurement.

Finally go here and punch in your data. In short order you'll have your numbers. JBM - Calculations - Trajectory

If you can't figure this at the range, how do you plan to do it in the field?

practice first,then huntIf you can't figure this at the range, how do you plan to do it in the field?

Practice asking on a forum what to dial for a given range?practice first,then hunt

I guess with the right cellphone service you could come back and ask before each shot...

But have you considered learning how to do it, and practicing to a point of proficiency?

See, your not asking how to catch fish. You're just asking for fish.

Why should anyone throw them to you?

I wonder the same thing as I have a 40 moa rail on this one but figure I'll fudge the value when doing the drop chart.

Your way may be better!

Also, yur not in the prry phone book.

Check your PM I'll send you one in a moment.

this chart works great ...berger bullets also had a chart I was not aware of and all the numbers I calculated with the two charts are close so I have a solid starting point ...thank you ..hopefully some trophy pics next week to follow...

This data would be the distance in inches between the line of bore and line of sight.

To get this:

This will give you the line of sight about the line of bore distance, fairly close.

- measure the diameter of the scope end bell at the end.
- measure the diameter of the barrel at the end of the scope end bell.
- measure the distance between the top of the end bell and the bottom of the barrel at the end of the end bell.
- Subtract 1/2 of end bell diameter AND 1/2 of the barrel diameter from the top of end bell to bottom of barrel measurement.

Finally go here and punch in your data. In short order you'll have your numbers. JBM - Calculations - Trajectory

Happy to be of service

If you're really splitting hairs the measurements used in most computer programs are referenced to the rifles bore at the muzzle. The distance you want in the calculations is the distance between a line from center of the objective lens to the center of the zero target, then perpendicular from that line to the center of the barrel's crown. That is the distance below the line of sight where the bullet is free to begin it's trajectory.

There is no situation where the bore and zero line of sight are parallel. The error in measuring from the scope to the chamber increases as the angle increases.