I use Litz's BC's to get in the ball park, they are actually pretty close.
He'll no doubt be calling you when he's ready to write his next book.
I have no idea where Litz does his testing, at sea level or 6000 feet, or any varying environmental conditions, no idea if the twist rate of his barrel is optimized for the bullet or not.
The tools are available for the hobbyist today to model BC's and apply that to a drop chart. This is only done by actual field testing and known velocities.
I suppose this doesn't make any real difference to cowboy action shooting or any less scientific endeavors.
