For a goal at 800 meters of at least 1200 fps
which combinations of BC and muzzle velocity work?
G7 BC 0.33 and velocity 2150 fps
G7 BC 0.32 and velocity 2175 fps
G7 BC 0.31 and velocity 2225 fps
G7 BC 0.30 and velocity 2250 fps
G7 BC 0.29 and velocity 2300 fps
G7 BC 0.28 and velocity 2350 fps
G7 BC 0.27 and velocity 2400 fps
G7 BC 0.26 and velocity 2450 fps
G7 BC 0.25 and velocity 2525 fps
G7 BC 0.24 and velocity 2575 fps
G7 BC 0.23 and velocity 2650 fps
G7 BC 0.22 and velocity 2725 fps
G7 BC 0.21 and velocity 2825 fps
G7 BC 0.20 and velocity 2925 fps
Notice that the relationship is not straight line. If you drop the BC from 0.21 to 0.20, you need an extra 100 fps to get the same velocity at range. But if you drop the BC from .31 to .30, you only need an extra 25 fps to make up the difference.
Increasing the BC is very helpful on the low end, as it allows you to drop the muzzle velocity significantly, decreasing barrel wear, barrel temperature, and perhaps muzzle blast and noise. But it is a case of diminishing returns. At least for a goal of 800 meters maximum effectiveness, a BC of 0.26, give or take, is good enough, while a BC of 0.22 is probably a good level for a minimum goal.
Since we know that an increase or decrease in barrel length adds or subtracts about 25 fps to a rifle round, we can add that factor. If you want a 2-inch shorter barrel, you can make up the loss of muzzle velocity (50 fps) with an increase in BC.