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Discussion in 'The Basics, Starting Out' started by jordanP., Mar 10, 2008.
sorry to ask but..... What is a come up chart and how do you use it.... thanks in advance...
It gives you information on how much scope adjustment needed for different distances. "Come ups" are usually in MOA so if you see a nice buck, range it at 490yds, you look at your come up chart for 500yds, turn your turret to the desired MOA and drop him. I have mine taped to my stock for easy refrence.
dont forget to include wind drift at those extened ranges. up down easy left right the hard part. i also put the temp and elevation so i dont have to remember.
To establish your "come up" chart you can use a ballistics calculator such as
JBM - Calculations - Trajectory
This will give you a first approximation of your trajectory. You take that chart to your long distance range and shoot your rifle with your load and make corrections to the "predicted" values by replacing them with the real values.
When you are done shooting you go back to JBM and rework your data. Typically the BC will not be as large of a number as the factory said. So with a little fiddling of numbers and tweaking, you will then have the factors that fit your rifle and your load for the temperature and conditions that you fired the data for. You can then use that to make drop charts for other temperatures and elevations.