Huntington sells RWS brass in 7 Rem Mag. Many consider it the best brass as good or better than Lapua.
Huntington Die Specialties :: Cases :: RWS Cases :: 7mm Rem. Mag | RWS
As for a program here is a free one. Takes some time to learn the inputs. JBM's program has worked for me. Also very useful in comparing potential bullets. For instance the 168 Berger and 180 Berger have almost identical wind drift. 168 shoots slightly flatter and 180 retains a bit more energy.
JBM - Calculations - Trajectory
Elevation input will drive you nuts till you realize that you need to input the actual pressures:
Barometric pressure adjustments
elevation pressure
500 29.27
1000 28.78
1500 28.29
2000 27.80
2500 27.32
2550 27.07
3000 26.82
3500 26.33
4000 25.84
4500 25.37
5000 24.90
5500 24.43
6500 23.57
7500 22.71
8000 22.23
9000 21.27
9500 20.79
10,000 20.31