Re-Launching BallisticXLR, Introducing BallisticXLR v9.1 w/ Banded Ballistic Coefficients
Some bullet companies provide ballistic coefficient data in velocity regimes or bands. In our never ending efforts to bring the most accurate Pejsa/Mayewski G1 model external ballistics resource in the world to the masses, I’ve now added banded ballistic coefficients in Version 9.1 of BallisticXLR. The banded BC’s feature as I’ve implemented them are simple to use with or without banding data.
If you don’t have banded values from your bullet manufacturer then you simply use their advertised G1 value. That value should be good to 300-400 yards. After that you should start recording your real drops so you can use those to reverse into the real numbers for longer ranges, thus building your own banding data. If they did provide banded values then you put in the BC and minimum velocity for that BC in each of 3 boxes on the inputs page and bango. You’re all good to go. The back end continuously applies BC value correction throughout the flight time. This feature helps get rid of hat mid-trajectory tendency to shoot high when using BC’s averaged for work at >600yrds and helps keep you from shooting low when using BC’s averaged for work at <600yrds.
Currently Sierra is the only bullet manufacturer I’m familiar with that extensively use banded ballistic coefficients. Hornady recently came out with range and twist specific values but those are still averaged values meant for use within particular distance/velocity windows, not banded values.
If you don’t understand this stuff, and who really does but a few of us, be sure to purchase a support entitlement from our Downloads and Support page. Then you can make me to all that math for you!