Ballistic FTE has always been good. There is a newer app called GeoBallistics, that has been developed by some local shooters I know. The GeoBallistics is set up to blue tooth with your kestrel and other devices to get up-to-date environmental data.
If on-line, I use this one: http://www.mega.nu:8080/traj_dat.html
I have used this on-line link on my phone in the deer stand and other places. It is a form of JBM, and I like the way it outputs the data, because I can copy and paste it into an Excel sheet and manipulate the columns and rows how I want them.
On your input, make sure if you use a G7 BC, that the drag setting is to G7, and not G1. If you are entering a G1 BC (which I do not recommend), make sure the setting is not on G7.
G1 BC is for a soft point, flat base bullet, and his heavily velocity dependent (as the bullet slows down, the G1 BC decreases).
G7 BC is for a BTHP bullet, which most rifle bullets are now. Use the G7 BC for more accurate longer range trajectory data with a 300 grain BTHP.