6mm Berger 120 LRHT

[wind gypsy]

Using a single number for BC, whether G1 or G7, is a fit of a generic drag curve (drag coefficient vs Mach number) to real measured drag data. It matters what range of speeds (Mach numbers) is considered in establishing the fit, because the error between the reference curve and the real bullet curve will be different at different speeds.

I think Litz, who is a purist and ELR fanatic (to a fault), typically includes data out to transonic (Mach =~ 1.2 or 13-1400 fps) which is the domain he is most interested in, but is way too slow/far for most useful ranges for most shooters. I think this is why there is sometimes a perceived disagreement between Berger/AB/Litz BC numbers and other manufacturers or experimental "truing" at sub-1k ranges.

The best thing to use is a Custom Drag Model (CDM, cute name since the drag coefficient vs Mach plots described above can be referred to as CD vs. M), which is using the actual drag throughout flight and is therefore accurate at all ranges/speeds (other than differences induced by gun/rifling).

The 0.321 avg from Litz's video was taken while he was only shooting 300 yards. 2800ish FPS MV. I think it's pretty unusual for BC to go up as velocity increases at distance.

Not arguing with anything you said, just pointing out some context of that particular measurement. A guy can look at all of the different AB drag models for the same bullet from different guns and in different conditions and see lots of variability.