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Posted: 8/20/2007 6:36:44 AM EDT
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So, I'm trying to cook up an excel spreadsheet to list comparative bullet drop/path information for various (any) cartridge loading. I found lots of formula and stuff, but I'm a bit bewildered. My spreadsheet looks like this: rows for each load/cartridge and columns for cartridge name, weight, velocity and ballistic coefficient (which I can obtain). Following that are yardage columns: 0, 25, 50, 75, 100 etc etc to 500 yds. I envision having cells to hold values for Sight Height, Temperature and Altitude. So, what do I put under the yardage columns to calculate the bullet's path based on the other values? This doesnt have to be super accurate, its just for ballparking POA/POI elevation differences between multiple cartridges at various ranges. Thanks! |
Yeah, I know about that one.... and could run it for all the various loads, and then just type-in the drop into my spreadsheet.... but that seems like a lot of typing/retyping. My goal is to have a spreadsheet that shows common ammo all on one page quick & dirty comparison. |
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"cook up an excel spreadsheet to list comparative bullet drop/path information for various (any) cartridge" That will be a large sheet for sure.I know what you are trying to do as I did the same to my favorite calibers /loads and gave up and bought a program to do that.It was called Silhouette Ballistics and although not an Excel file this saves as a proprietary .guntext but cured my listing attempt to something more manageable |
You can save the data to a text file and then import it into Excel. I just tried that, and it works. |
Only problem with that is its vertical, and has way too many data columns for my purpose. I only care about drop at XX yards (in columns) with maybe a dozen rows, each containing a different cartridge/loading. Like this: 
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Then you create a tab (another sheet in the file) for 'Import' and have a macro that will reformat (delete columns you don't want - then rotate the columns into rows), then copy from the 'import tab' to your main sheet. |
I'm gathering from the replies that the formula used by the Point-Blank program, and the myriad other ballistics prediction programs, not to mention most ammunition manufacturers simply isn't known.... and thus it would be easier to run the program for each possible combination, import the results, and create a master-spreadsheet to reformat all the cells into only what I'm looking for.  I'll keep digging..... if anybody else has the formula, please share. Thanks! |
No it's known, it's just not a simple algebraic equiation as it require integration (which means you have to have other tables setup when generating numbers ). And there are table lookups... For a 'simple' situation you can use the point mass program (in the Downloads section of the JBM site) to see how it works. Or you can download the spreadsheet ballistic calculator from the Documents section of www.MD-AR15.com (assuming you're a member) and try to reverse engineer what was done there. |
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