Here is some 30-378load data using GS custom bullets.The data can be found at
http://gsgroup.co.za/hvloads.html
30-378
308150HV.079
H4831
103
3850
BC .460 G5
S385
105
3850
308160HV.078
H1000
112
3700
BC .530 G5
S385
103
3700
308173HV.074
H1000
116[size=2]117
3600
BC .650 G5
S385
[font=verdana]
140141
3600
You will notice that the 30-378 drives the 173gr bullet at 3600fps.That bullet has a BC of .650.Punch that into your calculations.