I use Point Blank. It's free and seems to work quite well.
G7 is also available on the Vortex Optics website (LRBC - long range ballistic calculator). I like the validation featureon the computer you can go to gseven.com and it seems guite accurate. you can also print off drop charts, kinda handy
Any for Android?
I don't know if they have a PC version, but Ballistic AE for iphone is good. I've only been able to prove it to 600 so far, but it was still on the 8 inch gong at that range. A friend of mine has had the opportunity to push it further he said it worked to 1200, past that it was off a bit.
I'm looking for a Canadian distributor of RCBS LOAD ballistic software. They sell disc only and not online downloads.
Likely not the app but moreso the changes of conditions in that distance. I use isnipe for iphone (uses b. Litz's bc's) but it usually requires some tweaking because of condition variances. My range starts at 650 yards and ends at 1350, essentially shooting over a valley. Lots can change in that distance. It usually gets me close using chronographed velocity and kestrel with adjustments for down range observations.