Ok, I see and understand...

If you had these pills.....
0.224 77 gr smk
O.224 80 gr smk

O.243 75 gr hornady v max
O.243 87 gr hornady v max

O.308 168 gr hornady match
0.308 175 gr smk

And measured muzzle velocity, what data would you use, and how would you build a drop/ drift chart?
All are diffrent length barrels with known twist rates..

Chrono data would be an average of 10 shots, more if need be, temperature, and wind readings recorded at muzzle, shots taken at 100 yds.