To clarify my original post about using the proper drag model to calculate your bullets external ballistic, I thought I use a graph which shows all the drag models.
My ballistic program will let me calculate the exact BC of the bullet I’m shooting in my gun. It will also let me take my results and input the results to see what ballistic model best matches my bullet. With a little reverse engineering, I’ve been able to get my program to match my actual results to 1000 yards with .5 moa. The best I could get it to match using the G1 drag model was around 2.5 moa at 1000 yards.
These results were for my .308 I took moose hunting in Alaska, not that I was going to be shooting 1000 yards. They were for the Barnes .168 gr triple shock bullet BTHP.
The first graph shows all of the different drag models with my Barnes .168 gr triple shock in the upper porting of the graph. The G1 drag model I have an arrow pointed at is the modified and massaged G1 drag model used by many ballistic programs.
I then moved the Barnes .168 gr triple shock down to see which drag model best matched that bullet. As you can see it was an almost exact fit to the G7 drag model for VLD bullets. But you can also see, if I was using the G1 drag model that Sierra and most of the ballistic programs are using my results would not be very accurate.