BC's can vary largly from rifle to rifle. Best thing to do is fire your bullets out of your equipment at your velocities and determine where they are. Sorry! There is no clear cut answers on BC's.
I don't think .394 is too low. The 140XXX is not near as aerodynamic as the polymer tipped bullets available today. HP bullets with large HPs like the TS tend to have pretty lame BCs. I've also read studies about the drag the rings and even canelures cause.
I wouldn't be surprized if .394 was even alittle high.